diff --git a/boards/feather-m0/include/periph_conf.h b/boards/feather-m0/include/periph_conf.h
index 07498a6345..81353f743b 100644
--- a/boards/feather-m0/include/periph_conf.h
+++ b/boards/feather-m0/include/periph_conf.h
@@ -106,7 +106,9 @@ static const uart_conf_t uart_config[] = {
         .tx_pin = GPIO_PIN(PA, 10), /* TX pin */
         .mux    = GPIO_MUX_C,
         .rx_pad = UART_PAD_RX_3,
-        .tx_pad = UART_PAD_TX_2
+        .tx_pad = UART_PAD_TX_2,
+        .flags  = UART_FLAG_NONE,
+        .gclk_src = GCLK_CLKCTRL_GEN_GCLK0,
     }
 };
 
diff --git a/boards/mips-malta/Makefile.features b/boards/mips-malta/Makefile.features
index b2af0c6dce..e46d1ea23d 100644
--- a/boards/mips-malta/Makefile.features
+++ b/boards/mips-malta/Makefile.features
@@ -1,6 +1,5 @@
 # Put defined MCU peripherals here (in alphabetical order)
 FEATURES_PROVIDED += periph_timer
-FEATURES_PROVIDED += periph_uart
 
 # The board MPU family (used for grouping by the CI system)
 FEATURES_MCU_GROUP = mips32r2
diff --git a/boards/mips-malta/include/periph_conf.h b/boards/mips-malta/include/periph_conf.h
index 5baadafcda..a3b8d9d184 100644
--- a/boards/mips-malta/include/periph_conf.h
+++ b/boards/mips-malta/include/periph_conf.h
@@ -35,12 +35,6 @@ extern "C" {
 #define TIMER_0_CHANNELS    (3)
 /** @} */
 
-/**
- * @brief   No UART driver for this board currently
- *          Note this value must be set though (to 0)
- */
-#define UART_NUMOF          (0)
-
 #ifdef __cplusplus
 }
 #endif
diff --git a/boards/nucleo32-common/include/gpio_params.h b/boards/nucleo32-common/include/gpio_params.h
index 02e10792ae..fae5213270 100644
--- a/boards/nucleo32-common/include/gpio_params.h
+++ b/boards/nucleo32-common/include/gpio_params.h
@@ -26,19 +26,21 @@
 extern "C" {
 #endif
 
+#ifndef AUTO_INIT_LED0
+#define SAUL_GPIO_NUMOF (0U)
+#else
 /**
  * @brief    GPIO pin configuration
  */
 static const  saul_gpio_params_t saul_gpio_params[] =
 {
-#ifdef AUTO_INIT_LED0
     {
         .name = "LD3(green)",
         .pin = LED0_PIN,
         .mode = GPIO_OUT
     }
-#endif
 };
+#endif /* AUTO_INIT_LED0 */
 
 #ifdef __cplusplus
 }
diff --git a/boards/wsn430-common/board_init.c b/boards/wsn430-common/board_init.c
index adff4df65d..2eea62e9e5 100644
--- a/boards/wsn430-common/board_init.c
+++ b/boards/wsn430-common/board_init.c
@@ -14,7 +14,7 @@
 #include "debug.h"
 #include "uart_stdio.h"
 
-volatile static uint32_t __msp430_cpu_speed = MSP430_INITIAL_CPU_SPEED;
+static volatile uint32_t __msp430_cpu_speed = MSP430_INITIAL_CPU_SPEED;
 
 void msp430_init_dco(void);
 
diff --git a/cpu/kinetis/periph/timer.c b/cpu/kinetis/periph/timer.c
index ca1ea8130c..e7c9575191 100644
--- a/cpu/kinetis/periph/timer.c
+++ b/cpu/kinetis/periph/timer.c
@@ -132,16 +132,16 @@ static inline tim_t _lptmr_tim_t(uint8_t dev) {
 /* ****** PIT module functions ****** */
 
 /* Forward declarations */
-inline static int pit_init(uint8_t dev, uint32_t freq, timer_cb_t cb, void *arg);
-inline static int pit_set(uint8_t dev, uint32_t timeout);
-inline static int pit_set_absolute(uint8_t dev, uint32_t target);
-inline static int pit_clear(uint8_t dev);
-inline static uint32_t pit_read(uint8_t dev);
-inline static void pit_start(uint8_t dev);
-inline static void pit_stop(uint8_t dev);
-inline static void pit_irq_handler(tim_t dev);
+static inline int pit_init(uint8_t dev, uint32_t freq, timer_cb_t cb, void *arg);
+static inline int pit_set(uint8_t dev, uint32_t timeout);
+static inline int pit_set_absolute(uint8_t dev, uint32_t target);
+static inline int pit_clear(uint8_t dev);
+static inline uint32_t pit_read(uint8_t dev);
+static inline void pit_start(uint8_t dev);
+static inline void pit_stop(uint8_t dev);
+static inline void pit_irq_handler(tim_t dev);
 
-inline static void _pit_set_cb_config(uint8_t dev, timer_cb_t cb, void *arg)
+static inline void _pit_set_cb_config(uint8_t dev, timer_cb_t cb, void *arg)
 {
     /* set callback function */
     pit[dev].isr_ctx.cb = cb;
@@ -149,7 +149,7 @@ inline static void _pit_set_cb_config(uint8_t dev, timer_cb_t cb, void *arg)
 }
 
 /** use channel n-1 as prescaler */
-inline static void _pit_set_prescaler(uint8_t ch, uint32_t freq)
+static inline void _pit_set_prescaler(uint8_t ch, uint32_t freq)
 {
     /* Disable channel completely */
     PIT->CHANNEL[ch].TCTRL = 0x0;
@@ -158,7 +158,7 @@ inline static void _pit_set_prescaler(uint8_t ch, uint32_t freq)
     PIT->CHANNEL[ch].TCTRL = (PIT_TCTRL_TEN_MASK);
 }
 
-inline static void _pit_set_counter(uint8_t dev)
+static inline void _pit_set_counter(uint8_t dev)
 {
     const uint8_t ch = pit_config[dev].count_ch;
     /* Disable channel completely */
@@ -169,7 +169,7 @@ inline static void _pit_set_counter(uint8_t dev)
     PIT->CHANNEL[ch].TCTRL = pit[dev].tctrl;
 }
 
-inline static int pit_init(uint8_t dev, uint32_t freq, timer_cb_t cb, void *arg)
+static inline int pit_init(uint8_t dev, uint32_t freq, timer_cb_t cb, void *arg)
 {
     /* Turn on module clock gate */
     PIT_CLKEN();
@@ -204,7 +204,7 @@ inline static int pit_init(uint8_t dev, uint32_t freq, timer_cb_t cb, void *arg)
     return 0;
 }
 
-inline static int pit_set(uint8_t dev, uint32_t timeout)
+static inline int pit_set(uint8_t dev, uint32_t timeout)
 {
     const uint8_t ch = pit_config[dev].count_ch;
     /* Disable IRQs to minimize the number of lost ticks */
@@ -224,7 +224,7 @@ inline static int pit_set(uint8_t dev, uint32_t timeout)
     return 0;
 }
 
-inline static int pit_set_absolute(uint8_t dev, uint32_t target)
+static inline int pit_set_absolute(uint8_t dev, uint32_t target)
 {
     uint8_t ch = pit_config[dev].count_ch;
     /* Disable IRQs to minimize the number of lost ticks */
@@ -243,7 +243,7 @@ inline static int pit_set_absolute(uint8_t dev, uint32_t target)
     return 0;
 }
 
-inline static int pit_clear(uint8_t dev)
+static inline int pit_clear(uint8_t dev)
 {
     uint8_t ch = pit_config[dev].count_ch;
     /* Disable IRQs to minimize the number of lost ticks */
@@ -266,7 +266,7 @@ inline static int pit_clear(uint8_t dev)
     return 0;
 }
 
-inline static uint32_t pit_read(uint8_t dev)
+static inline uint32_t pit_read(uint8_t dev)
 {
     uint8_t ch = pit_config[dev].count_ch;
     if ((PIT->CHANNEL[ch].TCTRL & PIT_TCTRL_TEN_MASK) != 0) {
@@ -279,7 +279,7 @@ inline static uint32_t pit_read(uint8_t dev)
     }
 }
 
-inline static void pit_start(uint8_t dev)
+static inline void pit_start(uint8_t dev)
 {
     uint8_t ch = pit_config[dev].count_ch;
     if ((PIT->CHANNEL[ch].TCTRL & PIT_TCTRL_TEN_MASK) != 0) {
@@ -291,7 +291,7 @@ inline static void pit_start(uint8_t dev)
     PIT->CHANNEL[ch].TCTRL = pit[dev].tctrl;
 }
 
-inline static void pit_stop(uint8_t dev)
+static inline void pit_stop(uint8_t dev)
 {
     uint8_t ch = pit_config[dev].count_ch;
     if ((PIT->CHANNEL[ch].TCTRL & PIT_TCTRL_TEN_MASK) == 0) {
@@ -305,7 +305,7 @@ inline static void pit_stop(uint8_t dev)
     pit[dev].ldval = cval;
 }
 
-inline static void pit_irq_handler(tim_t dev)
+static inline void pit_irq_handler(tim_t dev)
 {
     uint8_t ch = pit_config[_pit_index(dev)].count_ch;
     pit_t *pit_ctx = &pit[_pit_index(dev)];
@@ -326,19 +326,19 @@ inline static void pit_irq_handler(tim_t dev)
 /* ****** LPTMR module functions ****** */
 
 /* Forward declarations */
-inline static int lptmr_init(uint8_t dev, uint32_t freq, timer_cb_t cb, void *arg);
-inline static int lptmr_set(uint8_t dev, uint16_t timeout);
-inline static int lptmr_set_absolute(uint8_t dev, uint16_t target);
-inline static int lptmr_clear(uint8_t dev);
-inline static uint16_t lptmr_read(uint8_t dev);
-inline static void lptmr_start(uint8_t dev);
-inline static void lptmr_stop(uint8_t dev);
-inline static void lptmr_irq_handler(tim_t tim);
+static inline int lptmr_init(uint8_t dev, uint32_t freq, timer_cb_t cb, void *arg);
+static inline int lptmr_set(uint8_t dev, uint16_t timeout);
+static inline int lptmr_set_absolute(uint8_t dev, uint16_t target);
+static inline int lptmr_clear(uint8_t dev);
+static inline uint16_t lptmr_read(uint8_t dev);
+static inline void lptmr_start(uint8_t dev);
+static inline void lptmr_stop(uint8_t dev);
+static inline void lptmr_irq_handler(tim_t tim);
 
 /**
  * @brief Read the prescaler register from the RTC as a reliable 47 bit time counter
  */
-inline static uint32_t _rtt_get_subtick(void)
+static inline uint32_t _rtt_get_subtick(void)
 {
     uint32_t tpr;
     uint32_t tsr;
@@ -364,7 +364,7 @@ inline static uint32_t _rtt_get_subtick(void)
     return (tsr << TIMER_RTC_SUBTICK_BITS) | tpr;
 }
 
-inline static void _lptmr_set_cb_config(uint8_t dev, timer_cb_t cb, void *arg)
+static inline void _lptmr_set_cb_config(uint8_t dev, timer_cb_t cb, void *arg)
 {
     /* set callback function */
     lptmr[dev].isr_ctx.cb = cb;
@@ -374,7 +374,7 @@ inline static void _lptmr_set_cb_config(uint8_t dev, timer_cb_t cb, void *arg)
 /**
  * @brief  Compute the LPTMR prescaler setting, see reference manual for details
  */
-inline static int32_t _lptmr_compute_prescaler(uint32_t freq) {
+static inline int32_t _lptmr_compute_prescaler(uint32_t freq) {
     uint32_t prescale = 0;
     if ((freq > LPTMR_BASE_FREQ) || (freq == 0)) {
         /* Frequency out of range */
@@ -402,7 +402,7 @@ inline static int32_t _lptmr_compute_prescaler(uint32_t freq) {
 /**
  * @brief  Update the offset between RTT and LPTMR
  */
-inline static void _lptmr_update_rtt_offset(uint8_t dev)
+static inline void _lptmr_update_rtt_offset(uint8_t dev)
 {
     lptmr[dev].rtt_offset = _rtt_get_subtick();
 }
@@ -410,12 +410,12 @@ inline static void _lptmr_update_rtt_offset(uint8_t dev)
 /**
  * @brief  Update the reference time point (CNR=0)
  */
-inline static void _lptmr_update_reference(uint8_t dev)
+static inline void _lptmr_update_reference(uint8_t dev)
 {
     lptmr[dev].reference = _rtt_get_subtick() + LPTMR_RELOAD_OVERHEAD - lptmr[dev].rtt_offset;
 }
 
-inline static void _lptmr_set_counter(uint8_t dev)
+static inline void _lptmr_set_counter(uint8_t dev)
 {
     _lptmr_update_reference(dev);
     LPTMR_Type *hw = lptmr_config[dev].dev;
@@ -425,7 +425,7 @@ inline static void _lptmr_set_counter(uint8_t dev)
     hw->CSR = lptmr[dev].csr;
 }
 
-inline static int lptmr_init(uint8_t dev, uint32_t freq, timer_cb_t cb, void *arg)
+static inline int lptmr_init(uint8_t dev, uint32_t freq, timer_cb_t cb, void *arg)
 {
     int32_t prescale = _lptmr_compute_prescaler(freq);
     if (prescale < 0) {
@@ -460,7 +460,7 @@ inline static int lptmr_init(uint8_t dev, uint32_t freq, timer_cb_t cb, void *ar
     return 0;
 }
 
-inline static uint16_t lptmr_read(uint8_t dev)
+static inline uint16_t lptmr_read(uint8_t dev)
 {
     LPTMR_Type *hw = lptmr_config[dev].dev;
     /* latch the current timer value into CNR */
@@ -468,7 +468,7 @@ inline static uint16_t lptmr_read(uint8_t dev)
     return lptmr[dev].reference + hw->CNR;
 }
 
-inline static int lptmr_set(uint8_t dev, uint16_t timeout)
+static inline int lptmr_set(uint8_t dev, uint16_t timeout)
 {
     /* Disable IRQs to minimize jitter */
     unsigned int mask = irq_disable();
@@ -484,7 +484,7 @@ inline static int lptmr_set(uint8_t dev, uint16_t timeout)
     return 0;
 }
 
-inline static int lptmr_set_absolute(uint8_t dev, uint16_t target)
+static inline int lptmr_set_absolute(uint8_t dev, uint16_t target)
 {
     /* Disable IRQs to minimize jitter */
     unsigned int mask = irq_disable();
@@ -501,7 +501,7 @@ inline static int lptmr_set_absolute(uint8_t dev, uint16_t target)
     return 0;
 }
 
-inline static int lptmr_clear(uint8_t dev)
+static inline int lptmr_clear(uint8_t dev)
 {
     /* Disable IRQs to minimize jitter */
     unsigned int mask = irq_disable();
@@ -517,7 +517,7 @@ inline static int lptmr_clear(uint8_t dev)
     return 0;
 }
 
-inline static void lptmr_start(uint8_t dev)
+static inline void lptmr_start(uint8_t dev)
 {
     if (lptmr[dev].running != 0) {
         /* Timer already running */
@@ -527,7 +527,7 @@ inline static void lptmr_start(uint8_t dev)
     _lptmr_set_counter(dev);
 }
 
-inline static void lptmr_stop(uint8_t dev)
+static inline void lptmr_stop(uint8_t dev)
 {
     if (lptmr[dev].running == 0) {
         /* Timer already stopped */
@@ -550,7 +550,7 @@ inline static void lptmr_stop(uint8_t dev)
     irq_restore(mask);
 }
 
-inline static void lptmr_irq_handler(tim_t tim)
+static inline void lptmr_irq_handler(tim_t tim)
 {
     uint8_t dev = _lptmr_index(tim);
     LPTMR_Type *hw = lptmr_config[dev].dev;
diff --git a/cpu/saml21/periph/timer.c b/cpu/saml21/periph/timer.c
index c67cb69fc7..71449637f5 100644
--- a/cpu/saml21/periph/timer.c
+++ b/cpu/saml21/periph/timer.c
@@ -48,6 +48,10 @@ static inline void _irq_enable(tim_t dev);
  */
 int timer_init(tim_t dev, unsigned long freq, timer_cb_t cb, void *arg)
 {
+    /* at the moment, the timer can only run at 1MHz */
+    if (freq != 1000000ul) {
+        return -1;
+    }
     /* configure GCLK0 to feed TC0 & TC1*/;
     GCLK->PCHCTRL[TC0_GCLK_ID].reg |= GCLK_PCHCTRL_CHEN | GCLK_PCHCTRL_GEN_GCLK0;
     while (!(GCLK->PCHCTRL[TC0_GCLK_ID].reg & GCLK_PCHCTRL_CHEN)) {}
diff --git a/cpu/stm32_common/periph/spi.c b/cpu/stm32_common/periph/spi.c
index dbf438a59b..843ed87439 100644
--- a/cpu/stm32_common/periph/spi.c
+++ b/cpu/stm32_common/periph/spi.c
@@ -117,8 +117,6 @@ int spi_init_cs(spi_t bus, spi_cs_t cs)
 
 int spi_acquire(spi_t bus, spi_cs_t cs, spi_mode_t mode, spi_clk_t clk)
 {
-    assert((clk >= SPI_CLK_100KHZ) && (clk <= SPI_CLK_10MHZ));
-
     /* lock bus */
     mutex_lock(&locks[bus]);
     /* enable SPI device clock */
diff --git a/cpu/stm32f4/periph/i2c.c b/cpu/stm32f4/periph/i2c.c
index 65f29f2e04..be3a2294e2 100644
--- a/cpu/stm32f4/periph/i2c.c
+++ b/cpu/stm32f4/periph/i2c.c
@@ -283,7 +283,7 @@ int i2c_read_bytes(i2c_t dev, uint8_t address, void *data, int length)
         }
 
         /* read byte */
-        *in++ = i2c->DR;
+        *(in++) = i2c->DR;
     }
 
     /* set STOP */
diff --git a/drivers/at30tse75x/at30tse75x.c b/drivers/at30tse75x/at30tse75x.c
index 5385b0928b..4549301b2c 100644
--- a/drivers/at30tse75x/at30tse75x.c
+++ b/drivers/at30tse75x/at30tse75x.c
@@ -110,11 +110,6 @@ int at30tse75x_set_resolution(const at30tse75x_t *dev, at30tse75x_resolution_t r
 {
     uint8_t config;
 
-    if(resolution < AT30TSE75X_RESOLUTION_9BIT ||
-       resolution > AT30TSE75X_RESOLUTION_12BIT) {
-        return -2;
-    }
-
     if(at30tse75x_get_config(dev, &config) != 0) {
         return -1;
     }
@@ -187,11 +182,6 @@ int at30tse75x_set_alarm_polarity(const at30tse75x_t *dev, at30tse75x_alarm_pola
 
 int at30tse75x_set_fault_tolerance(const at30tse75x_t *dev, at30tse75x_fault_tolerance_t tolerance)
 {
-    if(tolerance < AT30TSE75X_ALARM_AFTER_1 ||
-       tolerance > AT30TSE75X_ALARM_AFTER_6) {
-        return -2;
-    }
-
     uint8_t config;
     if(at30tse75x_get_config(dev, &config) != 0) {
         return -1;
diff --git a/drivers/at86rf2xx/at86rf2xx_getset.c b/drivers/at86rf2xx/at86rf2xx_getset.c
index e5558e720a..cb3e14f0b2 100644
--- a/drivers/at86rf2xx/at86rf2xx_getset.c
+++ b/drivers/at86rf2xx/at86rf2xx_getset.c
@@ -139,8 +139,10 @@ uint8_t at86rf2xx_get_chan(const at86rf2xx_t *dev)
 
 void at86rf2xx_set_chan(at86rf2xx_t *dev, uint8_t channel)
 {
-    if ((channel < AT86RF2XX_MIN_CHANNEL) ||
-        (channel > AT86RF2XX_MAX_CHANNEL) ||
+    if ((channel > AT86RF2XX_MAX_CHANNEL) ||
+#if AT86RF2XX_MIN_CHANNEL /* is zero for sub-GHz */
+        (channel < AT86RF2XX_MIN_CHANNEL) ||
+#endif
         (dev->netdev.chan == channel)) {
         return;
     }
diff --git a/drivers/at86rf2xx/at86rf2xx_netdev.c b/drivers/at86rf2xx/at86rf2xx_netdev.c
index a1ba95d726..0e757ee243 100644
--- a/drivers/at86rf2xx/at86rf2xx_netdev.c
+++ b/drivers/at86rf2xx/at86rf2xx_netdev.c
@@ -428,8 +428,11 @@ static int _set(netdev_t *netdev, netopt_t opt, const void *val, size_t len)
         case NETOPT_CHANNEL:
             assert(len == sizeof(uint16_t));
             uint8_t chan = (((const uint16_t *)val)[0]) & UINT8_MAX;
-            if ((chan < AT86RF2XX_MIN_CHANNEL)
-                || (chan > AT86RF2XX_MAX_CHANNEL)) {
+#if AT86RF2XX_MIN_CHANNEL
+            if (chan < AT86RF2XX_MIN_CHANNEL || chan > AT86RF2XX_MAX_CHANNEL) {
+#else
+            if (chan > AT86RF2XX_MAX_CHANNEL) {
+#endif /* AT86RF2XX_MIN_CHANNEL */
                 res = -EINVAL;
                 break;
             }
diff --git a/drivers/cc110x/cc110x-netdev.c b/drivers/cc110x/cc110x-netdev.c
index 5db238dbd7..016c2bfba8 100644
--- a/drivers/cc110x/cc110x-netdev.c
+++ b/drivers/cc110x/cc110x-netdev.c
@@ -41,6 +41,8 @@ static int _send(netdev_t *dev, const struct iovec *vector, unsigned count)
 {
     DEBUG("%s:%u\n", __func__, __LINE__);
 
+    (void)count;
+
     netdev_cc110x_t *netdev_cc110x = (netdev_cc110x_t*) dev;
     cc110x_pkt_t *cc110x_pkt = vector[0].iov_base;
 
@@ -135,7 +137,12 @@ static int _set(netdev_t *dev, netopt_t opt, const void *value, size_t value_len
             {
                 const uint8_t *arg = value;
                 uint8_t channel = arg[value_len-1];
-                if ((channel < CC110X_MIN_CHANNR) || (channel > CC110X_MAX_CHANNR)) {
+            #if CC110X_MIN_CHANNR
+                if (channel < CC110X_MIN_CHANNR) {
+                    return -EINVAL;
+                }
+            #endif /* CC110X_MIN_CHANNR */
+                if (channel > CC110X_MAX_CHANNR) {
                     return -EINVAL;
                 }
                 if (cc110x_set_channel(cc110x, channel) == -1) {
diff --git a/drivers/cc110x/cc110x-rxtx.c b/drivers/cc110x/cc110x-rxtx.c
index bbe216d292..878ccf678c 100644
--- a/drivers/cc110x/cc110x-rxtx.c
+++ b/drivers/cc110x/cc110x-rxtx.c
@@ -247,7 +247,7 @@ int cc110x_send(cc110x_t *dev, cc110x_pkt_t *packet)
 {
     DEBUG("cc110x: snd pkt to %u payload_length=%u\n",
             (unsigned)packet->address, (unsigned)packet->length-3);
-    uint8_t size;
+    unsigned size;
 
     switch (dev->radio_state) {
         case RADIO_RX_BUSY:
@@ -293,5 +293,5 @@ int cc110x_send(cc110x_t *dev, cc110x_pkt_t *packet)
 
     _tx_continue(dev);
 
-    return size;
+    return (int)size;
 }
diff --git a/drivers/cc110x/cc110x.c b/drivers/cc110x/cc110x.c
index 5107db8542..d66d222d7c 100644
--- a/drivers/cc110x/cc110x.c
+++ b/drivers/cc110x/cc110x.c
@@ -96,7 +96,7 @@ uint8_t cc110x_set_address(cc110x_t *dev, uint8_t address)
 {
     DEBUG("%s:%s:%u setting address %u\n", RIOT_FILE_RELATIVE, __func__,
             __LINE__, (unsigned)address);
-    if (!(address < MIN_UID) || (address > MAX_UID)) {
+    if (!(address < MIN_UID)) {
         if (dev->radio_state != RADIO_UNKNOWN) {
             cc110x_write_register(dev, CC110X_ADDR, address);
             dev->radio_address = address;
diff --git a/drivers/enc28j60/enc28j60.c b/drivers/enc28j60/enc28j60.c
index 7529b32336..2b9dd9312d 100644
--- a/drivers/enc28j60/enc28j60.c
+++ b/drivers/enc28j60/enc28j60.c
@@ -473,7 +473,7 @@ static int nd_set(netdev_t *netdev, netopt_t opt, const void *value, size_t valu
     }
 }
 
-const static netdev_driver_t netdev_driver_enc28j60 = {
+static const netdev_driver_t netdev_driver_enc28j60 = {
     .send = nd_send,
     .recv = nd_recv,
     .init = nd_init,
diff --git a/drivers/encx24j600/encx24j600.c b/drivers/encx24j600/encx24j600.c
index 28f6e01a99..491fdcbdd0 100644
--- a/drivers/encx24j600/encx24j600.c
+++ b/drivers/encx24j600/encx24j600.c
@@ -70,7 +70,7 @@ static int _init(netdev_t *dev);
 static void _isr(netdev_t *dev);
 static int _get(netdev_t *dev, netopt_t opt, void *value, size_t max_len);
 
-const static netdev_driver_t netdev_driver_encx24j600 = {
+static const netdev_driver_t netdev_driver_encx24j600 = {
     .send = _send,
     .recv = _recv,
     .init = _init,
diff --git a/drivers/include/nrf24l01p.h b/drivers/include/nrf24l01p.h
index 615a1d9f32..56fe845358 100644
--- a/drivers/include/nrf24l01p.h
+++ b/drivers/include/nrf24l01p.h
@@ -322,7 +322,8 @@ int nrf24l01p_set_address_width(const nrf24l01p_t *dev, nrf24l01p_aw_t aw);
 * @return           0 on success.
 * @return           -1 on error.
 */
-int nrf24l01p_set_payload_width(const nrf24l01p_t *dev, nrf24l01p_rx_pipe_t pipe, char width);
+int nrf24l01p_set_payload_width(const nrf24l01p_t *dev,
+                                nrf24l01p_rx_pipe_t pipe, uint8_t width);
 
 /**
 * @brief   Set the TX address for the nrf24l01+ transceiver (byte array).
diff --git a/drivers/include/sdcard_spi.h b/drivers/include/sdcard_spi.h
index 558d2276c2..db05a73979 100644
--- a/drivers/include/sdcard_spi.h
+++ b/drivers/include/sdcard_spi.h
@@ -39,7 +39,7 @@ extern "C" {
 /**
  * @brief   CID register see section 5.2 in SD-Spec v5.00
  */
-struct {
+typedef struct {
     uint8_t MID;              /**< Manufacturer ID */
     char OID[SD_SIZE_OF_OID]; /**< OEM/Application ID*/
     char PNM[SD_SIZE_OF_PNM]; /**< Product name */
@@ -47,13 +47,13 @@ struct {
     uint32_t PSN;             /**< Product serial number */
     uint16_t MDT;             /**< Manufacturing date */
     uint8_t CID_CRC;          /**< CRC7 checksum */
-} typedef cid_t;
+} cid_t;
 
 /**
  * @brief   CSD register with csd structure version 1.0
  *          see section 5.3.2 in SD-Spec v5.00
  */
-struct {
+typedef struct {
     uint8_t CSD_STRUCTURE : 2;        /**< see section 5.3.2 in SD-Spec v5.00 */
     uint8_t TAAC : 8;                 /**< see section 5.3.2 in SD-Spec v5.00 */
     uint8_t NSAC : 8;                 /**< see section 5.3.2 in SD-Spec v5.00 */
@@ -83,13 +83,13 @@ struct {
     uint8_t TMP_WRITE_PROTECT : 1;    /**< see section 5.3.2 in SD-Spec v5.00 */
     uint8_t FILE_FORMAT : 2;          /**< see section 5.3.2 in SD-Spec v5.00 */
     uint8_t CSD_CRC : 8;              /**< see section 5.3.2 in SD-Spec v5.00 */
-} typedef csd_v1_t;
+} csd_v1_t;
 
 /**
  * @brief   CSD register with csd structure version 2.0
  *          see section 5.3.3 in SD-Spec v5.00
  */
-struct {
+typedef struct {
     uint8_t CSD_STRUCTURE : 2;        /**< see section 5.3.3 in SD-Spec v5.00 */
     uint8_t TAAC : 8;                 /**< see section 5.3.3 in SD-Spec v5.00 */
     uint8_t NSAC : 8;                 /**< see section 5.3.3 in SD-Spec v5.00 */
@@ -114,20 +114,20 @@ struct {
     uint8_t TMP_WRITE_PROTECT : 1;    /**< see section 5.3.3 in SD-Spec v5.00 */
     uint8_t FILE_FORMAT : 2;          /**< see section 5.3.3 in SD-Spec v5.00 */
     uint8_t CSD_CRC : 8;              /**< see section 5.3.3 in SD-Spec v5.00 */
-} typedef csd_v2_t;
+} csd_v2_t;
 
 /**
  * @brief   CSD register (see section 5.3 in SD-Spec v5.00)
  */
-union {
+typedef union {
     csd_v1_t v1;   /**< see section 5.3.2 in SD-Spec v5.00 */
     csd_v2_t v2;   /**< see section 5.3.3 in SD-Spec v5.00 */
-} typedef csd_t;
+} csd_t;
 
 /**
  * @brief   SD status register (see section 4.10.2 in SD-Spec v5.00)
  */
-struct {
+typedef struct {
     uint32_t SIZE_OF_PROTECTED_AREA : 32;   /**< see section 4.10.2 in SD-Spec v5.00 */
     uint32_t SUS_ADDR : 22;                 /**< see section 4.10.2.12 in SD-Spec v5.00 */
     uint32_t VSC_AU_SIZE : 10;              /**< see section 4.10.2.11 in SD-Spec v5.00 */
@@ -143,7 +143,7 @@ struct {
     uint8_t  AU_SIZE : 4;                   /**< see section 4.10.2.4 in SD-Spec v5.00 */
     uint8_t  DAT_BUS_WIDTH : 2;             /**< see section 4.10.2 in SD-Spec v5.00 */
     uint8_t  SECURED_MODE : 1;              /**< see section 4.10.2 in SD-Spec v5.00 */
-} typedef sd_status_t;
+} sd_status_t;
 
 /**
  * @brief   version type of SD-card
@@ -184,7 +184,7 @@ typedef struct {
 /**
  * @brief   Device descriptor for sdcard_spi
  */
-struct {
+typedef struct {
     sdcard_spi_params_t params;     /**< parameters for pin and spi config */
     spi_clk_t spi_clk;              /**< active SPI clock speed */
     bool use_block_addr;            /**< true if block adressing (vs. byte adressing) is used */
@@ -193,7 +193,7 @@ struct {
     int csd_structure;              /**< version of the CSD register structure */
     cid_t cid;                      /**< CID register */
     csd_t csd;                      /**< CSD register */
-} typedef sdcard_spi_t;
+} sdcard_spi_t;
 
 /**
  * @brief              Initializes the sd-card with the given parameters in sdcard_spi_t structure.
diff --git a/drivers/kw2xrf/kw2xrf_tm.c b/drivers/kw2xrf/kw2xrf_tm.c
index 576459597d..e0e9d6b24f 100644
--- a/drivers/kw2xrf/kw2xrf_tm.c
+++ b/drivers/kw2xrf/kw2xrf_tm.c
@@ -23,7 +23,7 @@
 
 #ifdef KW2XRF_TESTMODE
 
-inline static void enable_xcvr_test_mode(kw2xrf_t *dev)
+static inline void enable_xcvr_test_mode(kw2xrf_t *dev)
 {
     uint8_t reg;
 
@@ -36,7 +36,7 @@ inline static void enable_xcvr_test_mode(kw2xrf_t *dev)
     kw2xrf_write_iregs(dev, MKW2XDMI_TESTMODE_CTRL, &reg, 1);
 }
 
-inline static void disable_xcvr_test_mode(kw2xrf_t *dev)
+static inline void disable_xcvr_test_mode(kw2xrf_t *dev)
 {
     uint8_t reg;
 
diff --git a/drivers/nrf24l01p/nrf24l01p.c b/drivers/nrf24l01p/nrf24l01p.c
index 5311cd64ea..7d2dba8709 100644
--- a/drivers/nrf24l01p/nrf24l01p.c
+++ b/drivers/nrf24l01p/nrf24l01p.c
@@ -320,7 +320,8 @@ int nrf24l01p_set_address_width(const nrf24l01p_t *dev, nrf24l01p_aw_t aw)
     return nrf24l01p_write_reg(dev, REG_SETUP_AW, aw_setup);
 }
 
-int nrf24l01p_set_payload_width(const nrf24l01p_t *dev, nrf24l01p_rx_pipe_t pipe, char width)
+int nrf24l01p_set_payload_width(const nrf24l01p_t *dev,
+                                nrf24l01p_rx_pipe_t pipe, uint8_t width)
 {
     char pipe_pw_address;
 
@@ -353,7 +354,7 @@ int nrf24l01p_set_payload_width(const nrf24l01p_t *dev, nrf24l01p_rx_pipe_t pipe
             return -1;
     }
 
-    if (width < 0) {
+    if (width == 0) {
         return -1;
     }
 
diff --git a/drivers/pn532/pn532.c b/drivers/pn532/pn532.c
index a78df2ac93..ffa38fb89a 100644
--- a/drivers/pn532/pn532.c
+++ b/drivers/pn532/pn532.c
@@ -144,9 +144,9 @@ int pn532_init(pn532_t *dev, const pn532_params_t *params, pn532_mode_t mode)
     return 0;
 }
 
-static unsigned char chksum(char *b, unsigned len)
+static uint8_t chksum(uint8_t *b, unsigned len)
 {
-    unsigned char c = 0x00;
+    uint8_t c = 0x00;
 
     while (len--) {
         c -= *b++;
@@ -165,7 +165,7 @@ static void reverse(char *buff, unsigned len)
 }
 #endif
 
-static int _write(const pn532_t *dev, char *buff, unsigned len)
+static int _write(const pn532_t *dev, uint8_t *buff, unsigned len)
 {
     int ret = -1;
 
@@ -197,7 +197,7 @@ static int _write(const pn532_t *dev, char *buff, unsigned len)
     return ret;
 }
 
-static int _read(const pn532_t *dev, char *buff, unsigned len)
+static int _read(const pn532_t *dev, uint8_t *buff, unsigned len)
 {
     int ret = -1;
 
@@ -231,9 +231,10 @@ static int _read(const pn532_t *dev, char *buff, unsigned len)
     return ret;
 }
 
-static int send_cmd(const pn532_t *dev, char *buff, unsigned len)
+static int send_cmd(const pn532_t *dev, uint8_t *buff, unsigned len)
 {
-    unsigned pos, checksum;
+    unsigned pos;
+    uint8_t checksum;
 
     buff[0] = 0x00;
     buff[1] = 0x00;
@@ -271,7 +272,7 @@ static void wait_ready(pn532_t *dev)
 }
 
 /* Returns >0 payload len (or <0 received len but not as expected) */
-static int read_command(const pn532_t *dev, char *buff, unsigned len, int expected_cmd)
+static int read_command(const pn532_t *dev, uint8_t *buff, unsigned len, int expected_cmd)
 {
     int r;
     unsigned j, fi, lp, lc;
@@ -335,7 +336,7 @@ static int read_command(const pn532_t *dev, char *buff, unsigned len, int expect
 }
 
 /* Returns 0 if OK, <0 otherwise */
-static int send_check_ack(pn532_t *dev, char *buff, unsigned len)
+static int send_check_ack(pn532_t *dev, uint8_t *buff, unsigned len)
 {
     if (send_cmd(dev, buff, len) > 0) {
         static char ack[] = { 0x00, 0x00, 0xff, 0x00, 0xff, 0x00 };
@@ -357,7 +358,7 @@ static int send_check_ack(pn532_t *dev, char *buff, unsigned len)
 }
 
 /* sendl: send length, recvl: receive payload length */
-static int send_rcv(pn532_t *dev, char *buff, unsigned sendl, unsigned recvl)
+static int send_rcv(pn532_t *dev, uint8_t *buff, unsigned sendl, unsigned recvl)
 {
     assert(dev != NULL);
 
@@ -374,7 +375,7 @@ static int send_rcv(pn532_t *dev, char *buff, unsigned sendl, unsigned recvl)
 int pn532_fw_version(pn532_t *dev, uint32_t *fw_ver)
 {
     unsigned ret = -1;
-    char buff[PN532_BUFFER_LEN];
+    uint8_t buff[PN532_BUFFER_LEN];
 
     buff[BUFF_CMD_START] = CMD_FIRMWARE_VERSION;
 
@@ -392,7 +393,7 @@ int pn532_fw_version(pn532_t *dev, uint32_t *fw_ver)
 int pn532_read_reg(pn532_t *dev, char *out, unsigned addr)
 {
     int ret = -1;
-    char buff[PN532_BUFFER_LEN];
+    uint8_t buff[PN532_BUFFER_LEN];
 
     buff[BUFF_CMD_START     ] = CMD_READ_REG;
     buff[BUFF_DATA_START    ] = (addr >> 8) & 0xff;
@@ -408,7 +409,7 @@ int pn532_read_reg(pn532_t *dev, char *out, unsigned addr)
 
 int pn532_write_reg(pn532_t *dev, unsigned addr, char val)
 {
-    char buff[PN532_BUFFER_LEN];
+    uint8_t buff[PN532_BUFFER_LEN];
 
     buff[BUFF_CMD_START     ] = CMD_WRITE_REG;
     buff[BUFF_DATA_START    ] = (addr >> 8) & 0xff;
@@ -418,7 +419,7 @@ int pn532_write_reg(pn532_t *dev, unsigned addr, char val)
     return send_rcv(dev, buff, 3, 0);
 }
 
-static int _rf_configure(pn532_t *dev, char *buff, unsigned cfg_item, char *config,
+static int _rf_configure(pn532_t *dev, uint8_t *buff, unsigned cfg_item, char *config,
                          unsigned cfg_len)
 {
     buff[BUFF_CMD_START ] = CMD_RF_CONFIG;
@@ -430,7 +431,7 @@ static int _rf_configure(pn532_t *dev, char *buff, unsigned cfg_item, char *conf
     return send_rcv(dev, buff, cfg_len + 1, 0);
 }
 
-static int _set_act_retries(pn532_t *dev, char *buff, unsigned max_retries)
+static int _set_act_retries(pn532_t *dev, uint8_t *buff, unsigned max_retries)
 {
     char rtrcfg[] = { 0xff, 0x01, max_retries & 0xff };
 
@@ -439,7 +440,7 @@ static int _set_act_retries(pn532_t *dev, char *buff, unsigned max_retries)
 
 int pn532_sam_configuration(pn532_t *dev, pn532_sam_conf_mode_t mode, unsigned timeout)
 {
-    char buff[PN532_BUFFER_LEN];
+    uint8_t buff[PN532_BUFFER_LEN];
 
     buff[BUFF_CMD_START     ] = CMD_SAM_CONFIG;
     buff[BUFF_DATA_START    ] = (char)mode;
@@ -449,7 +450,7 @@ int pn532_sam_configuration(pn532_t *dev, pn532_sam_conf_mode_t mode, unsigned t
     return send_rcv(dev, buff, 3, 0);
 }
 
-static int _list_passive_targets(pn532_t *dev, char *buff, pn532_target_t target,
+static int _list_passive_targets(pn532_t *dev, uint8_t *buff, pn532_target_t target,
                                  unsigned max, unsigned recvl)
 {
     buff[BUFF_CMD_START] = CMD_LIST_PASSIVE;
@@ -464,7 +465,7 @@ int pn532_get_passive_iso14443a(pn532_t *dev, nfc_iso14443a_t *out,
                                 unsigned max_retries)
 {
     int ret = -1;
-    char buff[PN532_BUFFER_LEN];
+    uint8_t buff[PN532_BUFFER_LEN];
 
     if (_set_act_retries(dev, buff, max_retries) == 0) {
         ret = _list_passive_targets(dev, buff, PN532_BR_106_ISO_14443_A, 1,
@@ -504,7 +505,7 @@ int pn532_get_passive_iso14443a(pn532_t *dev, nfc_iso14443a_t *out,
 
 void pn532_deselect_passive(pn532_t *dev, unsigned target_id)
 {
-    char buff[PN532_BUFFER_LEN];
+    uint8_t buff[PN532_BUFFER_LEN];
 
     buff[BUFF_CMD_START ] = CMD_DESELECT;
     buff[BUFF_DATA_START] = target_id;
@@ -514,7 +515,7 @@ void pn532_deselect_passive(pn532_t *dev, unsigned target_id)
 
 void pn532_release_passive(pn532_t *dev, unsigned target_id)
 {
-    char buff[PN532_BUFFER_LEN];
+    uint8_t buff[PN532_BUFFER_LEN];
 
     buff[BUFF_CMD_START ] = CMD_RELEASE;
     buff[BUFF_DATA_START] = target_id;
@@ -526,7 +527,7 @@ int pn532_mifareclassic_authenticate(pn532_t *dev, nfc_iso14443a_t *card,
                                      pn532_mifare_key_t keyid, char *key, unsigned block)
 {
     int ret = -1;
-    char buff[PN532_BUFFER_LEN];
+    uint8_t buff[PN532_BUFFER_LEN];
 
     buff[BUFF_CMD_START     ] = CMD_DATA_EXCHANGE;
     buff[BUFF_DATA_START    ] = card->target;
@@ -558,7 +559,7 @@ int pn532_mifareclassic_write(pn532_t *dev, char *idata, nfc_iso14443a_t *card,
                               unsigned block)
 {
     int ret = -1;
-    char buff[PN532_BUFFER_LEN];
+    uint8_t buff[PN532_BUFFER_LEN];
 
     if (card->auth) {
 
@@ -580,7 +581,7 @@ static int pn532_mifare_read(pn532_t *dev, char *odata, nfc_iso14443a_t *card,
                              unsigned block, unsigned len)
 {
     int ret = -1;
-    char buff[PN532_BUFFER_LEN];
+    uint8_t buff[PN532_BUFFER_LEN];
 
     buff[BUFF_CMD_START     ] = CMD_DATA_EXCHANGE;
     buff[BUFF_DATA_START    ] = card->target;
@@ -612,7 +613,7 @@ int pn532_mifareulight_read(pn532_t *dev, char *odata, nfc_iso14443a_t *card,
     return pn532_mifare_read(dev, odata, card, page, 32);
 }
 
-static int send_rcv_apdu(pn532_t *dev, char *buff, unsigned slen, unsigned rlen)
+static int send_rcv_apdu(pn532_t *dev, uint8_t *buff, unsigned slen, unsigned rlen)
 {
     int ret;
 
@@ -635,7 +636,7 @@ static int send_rcv_apdu(pn532_t *dev, char *buff, unsigned slen, unsigned rlen)
 int pn532_iso14443a_4_activate(pn532_t *dev, nfc_iso14443a_t *card)
 {
     int ret;
-    char buff[PN532_BUFFER_LEN];
+    uint8_t buff[PN532_BUFFER_LEN];
 
     /* select app ndef tag */
     buff[BUFF_CMD_START      ] = CMD_DATA_EXCHANGE;
@@ -680,7 +681,7 @@ int pn532_iso14443a_4_read(pn532_t *dev, char *odata, nfc_iso14443a_t *card,
                            unsigned offset, char len)
 {
     int ret;
-    char buff[PN532_BUFFER_LEN];
+    uint8_t buff[PN532_BUFFER_LEN];
 
     buff[BUFF_CMD_START     ] = CMD_DATA_EXCHANGE;
     buff[BUFF_DATA_START    ] = card->target;
diff --git a/drivers/sdcard_spi/sdcard_spi.c b/drivers/sdcard_spi/sdcard_spi.c
index f661b5a239..45c62fdffe 100644
--- a/drivers/sdcard_spi/sdcard_spi.c
+++ b/drivers/sdcard_spi/sdcard_spi.c
@@ -207,7 +207,7 @@ static sd_init_fsm_state_t _init_sd_fsm_step(sdcard_spi_t *card, sd_init_fsm_sta
                     return SD_INIT_SEND_CMD58;
                 }
                 acmd41_hcs_retries++;
-            } while (INIT_CMD_RETRY_CNT < 0 || acmd41_hcs_retries <= INIT_CMD_RETRY_CNT);;
+            } while ((INIT_CMD_RETRY_CNT < 0) || (acmd41_hcs_retries <= (int)INIT_CMD_RETRY_CNT));
             _unselect_card_spi(card);
             return SD_INIT_CARD_UNKNOWN;
 
@@ -223,7 +223,7 @@ static sd_init_fsm_state_t _init_sd_fsm_step(sdcard_spi_t *card, sd_init_fsm_sta
                     return SD_INIT_SEND_CMD16;
                 }
                 acmd41_retries++;
-            } while (INIT_CMD_RETRY_CNT < 0 || acmd41_retries <= INIT_CMD_RETRY_CNT);
+            } while ((INIT_CMD_RETRY_CNT < 0) || (acmd41_retries <= (int)INIT_CMD_RETRY_CNT));
 
             DEBUG("ACMD41: [ERROR]\n");
             return SD_INIT_SEND_CMD1;
@@ -373,7 +373,7 @@ static inline bool _wait_for_not_busy(sdcard_spi_t *card, int32_t max_retries)
 
     do {
         if (_dyn_spi_rxtx_byte(card, SD_CARD_DUMMY_BYTE, &read_byte) == 1) {
-            if (read_byte == 0xFF) {
+            if ((uint8_t)read_byte == 0xFF) {
                 DEBUG("_wait_for_not_busy: [OK]\n");
                 return true;
             }
diff --git a/drivers/sx127x/sx127x_netdev.c b/drivers/sx127x/sx127x_netdev.c
index 4540d7c6f9..7ec0d50a9a 100644
--- a/drivers/sx127x/sx127x_netdev.c
+++ b/drivers/sx127x/sx127x_netdev.c
@@ -361,6 +361,8 @@ static int _get(netdev_t *netdev, netopt_t opt, void *val, size_t max_len)
 
 static int _set(netdev_t *netdev, netopt_t opt, const void *val, size_t len)
 {
+    (void)len; /* unused when compiled without debug, assert empty */
+
     sx127x_t *dev = (sx127x_t*) netdev;
     int res = -ENOTSUP;
 
@@ -386,8 +388,7 @@ static int _set(netdev_t *netdev, netopt_t opt, const void *val, size_t len)
         case NETOPT_BANDWIDTH:
             assert(len <= sizeof(uint8_t));
             uint8_t bw = *((const uint8_t *)val);
-            if (bw < LORA_BW_125_KHZ ||
-                bw > LORA_BW_500_KHZ) {
+            if (bw > LORA_BW_500_KHZ) {
                 res = -EINVAL;
                 break;
             }
@@ -397,8 +398,7 @@ static int _set(netdev_t *netdev, netopt_t opt, const void *val, size_t len)
         case NETOPT_SPREADING_FACTOR:
             assert(len <= sizeof(uint8_t));
             uint8_t sf = *((const uint8_t *)val);
-            if (sf < LORA_SF6 ||
-                sf > LORA_SF12) {
+            if ((sf < LORA_SF6) || (sf > LORA_SF12)) {
                 res = -EINVAL;
                 break;
             }
@@ -408,8 +408,7 @@ static int _set(netdev_t *netdev, netopt_t opt, const void *val, size_t len)
         case NETOPT_CODING_RATE:
             assert(len <= sizeof(uint8_t));
             uint8_t cr = *((const uint8_t *)val);
-            if (cr < LORA_CR_4_5 ||
-                cr > LORA_CR_4_8) {
+            if ((cr < LORA_CR_4_5) || (cr > LORA_CR_4_8)) {
                 res = -EINVAL;
                 break;
             }
diff --git a/drivers/tcs37727/tcs37727.c b/drivers/tcs37727/tcs37727.c
index bcbabb7634..11a7acfd2a 100644
--- a/drivers/tcs37727/tcs37727.c
+++ b/drivers/tcs37727/tcs37727.c
@@ -106,7 +106,7 @@ void tcs37727_set_rgbc_standby(const tcs37727_t *dev)
     i2c_release(BUS);
 }
 
-static uint8_t tcs37727_trim_gain(tcs37727_t *dev, int rawc)
+static uint8_t tcs37727_trim_gain(tcs37727_t *dev, int32_t rawc)
 {
     uint8_t reg_again = 0;
     int val_again = dev->again;
diff --git a/pkg/emb6/Makefile.include b/pkg/emb6/Makefile.include
index ab9e85a0e4..6b0e006fde 100644
--- a/pkg/emb6/Makefile.include
+++ b/pkg/emb6/Makefile.include
@@ -5,6 +5,9 @@ EMB6_CONTRIB := $(RIOTBASE)/pkg/emb6/contrib
 INCLUDES += -I$(PKG_BUILDDIR)/target
 INCLUDES += -I$(RIOTBASE)/pkg/emb6/include
 
+CFLAGS += -Wno-unused-parameter -Wno-unused-function -Wno-type-limits
+CFLAGS += -Wno-sign-compare -Wno-missing-field-initializers
+
 ifeq (,$(filter emb6_router,$(USEMODULE)))
   CFLAGS += -DEMB6_CONF_ROUTER=FALSE
 endif
diff --git a/pkg/nordic_softdevice_ble/Makefile.include b/pkg/nordic_softdevice_ble/Makefile.include
index 4db3a86812..70a6563e3e 100644
--- a/pkg/nordic_softdevice_ble/Makefile.include
+++ b/pkg/nordic_softdevice_ble/Makefile.include
@@ -20,6 +20,8 @@ CFLAGS += -DNRF52 \
 		  -DSOFTDEVICE_PRESENT \
 		  -DS132
 
+CFLAGS += -Wno-pedantic -Wno-unused-parameter -Wno-sign-compare
+
 # Nordic's ble_6lowpan.a is compiled with hard-float
 # so set this, otherwise linking fails
 CFLAGS_FPU := -mfloat-abi=hard -mfpu=fpv4-sp-d16
@@ -29,4 +31,3 @@ DIRS += \
 		$(NORDIC_SRCS)/components/softdevice/common/softdevice_handler \
 		$(NORDIC_SRCS)/components/ble/common \
 		$(NORDIC_SRCS)/components/iot/ble_ipsp
-
diff --git a/pkg/openthread/contrib/netdev/openthread_netdev.c b/pkg/openthread/contrib/netdev/openthread_netdev.c
index 6c294cd207..348da5ac9c 100644
--- a/pkg/openthread/contrib/netdev/openthread_netdev.c
+++ b/pkg/openthread/contrib/netdev/openthread_netdev.c
@@ -71,6 +71,7 @@ void otTaskletsSignalPending(otInstance *aInstance) {
 }
 
 static void *_openthread_event_loop(void *arg) {
+    (void)arg;
     _pid = thread_getpid();
 
     /* enable OpenThread UART */
diff --git a/pkg/openthread/contrib/platform_alarm.c b/pkg/openthread/contrib/platform_alarm.c
index 6a6f3d6f32..52b8d48caa 100644
--- a/pkg/openthread/contrib/platform_alarm.c
+++ b/pkg/openthread/contrib/platform_alarm.c
@@ -40,6 +40,9 @@ static msg_t ot_alarm_msg;
  */
 void otPlatAlarmStartAt(otInstance *aInstance, uint32_t aT0, uint32_t aDt)
 {
+    (void)aInstance;
+    (void)aT0;
+
     DEBUG("openthread: otPlatAlarmStartAt: aT0: %" PRIu32 ", aDT: %" PRIu32 "\n", aT0, aDt);
     ot_alarm_msg.type = OPENTHREAD_XTIMER_MSG_TYPE_EVENT;
 
@@ -55,6 +58,7 @@ void otPlatAlarmStartAt(otInstance *aInstance, uint32_t aT0, uint32_t aDt)
 /* OpenThread will call this to stop alarms */
 void otPlatAlarmStop(otInstance *aInstance)
 {
+    (void)aInstance;
     DEBUG("openthread: otPlatAlarmStop\n");
     xtimer_remove(&ot_timer);
 }
diff --git a/pkg/openthread/contrib/platform_diag.c b/pkg/openthread/contrib/platform_diag.c
index 63092fb021..e398c1feef 100644
--- a/pkg/openthread/contrib/platform_diag.c
+++ b/pkg/openthread/contrib/platform_diag.c
@@ -25,6 +25,9 @@ void otPlatDiagProcess(int argc, char *argv[], char *aOutput, size_t aOutputMaxL
 {
     /* add more plarform specific diagnostics features here */
     (void)argc;
+    (void)argv;
+    (void)aOutput;
+    (void)aOutputMaxLen;
 }
 
 void otPlatDiagModeSet(bool aMode)
diff --git a/pkg/openthread/contrib/platform_functions_wrapper.c b/pkg/openthread/contrib/platform_functions_wrapper.c
index e3eb45650b..2eeead8d42 100644
--- a/pkg/openthread/contrib/platform_functions_wrapper.c
+++ b/pkg/openthread/contrib/platform_functions_wrapper.c
@@ -98,11 +98,17 @@ uint8_t ot_exec_command(otInstance *ot_instance, const char* command, void *arg,
 
 void output_bytes(const char* name, const uint8_t *aBytes, uint8_t aLength)
 {
+#if ENABLE_DEBUG
     DEBUG("%s: ", name);
     for (int i = 0; i < aLength; i++) {
         DEBUG("%02x", aBytes[i]);
     }
     DEBUG("\n");
+#else
+    (void)name;
+    (void)aBytes;
+    (void)aLength;
+#endif
 }
 
 OT_COMMAND ot_channel(otInstance* ot_instance, void* arg, void* answer) {
@@ -119,6 +125,8 @@ OT_COMMAND ot_channel(otInstance* ot_instance, void* arg, void* answer) {
 }
 
 OT_COMMAND ot_eui64(otInstance* ot_instance, void* arg, void* answer) {
+    (void)arg;
+
     if (answer != NULL) {
         otExtAddress address;
         otLinkGetFactoryAssignedIeeeEui64(ot_instance, &address);
@@ -132,6 +140,8 @@ OT_COMMAND ot_eui64(otInstance* ot_instance, void* arg, void* answer) {
 
 
 OT_COMMAND ot_extaddr(otInstance* ot_instance, void* arg, void* answer) {
+    (void)arg;
+
     if (answer != NULL) {
         answer = (void*)otLinkGetExtendedAddress(ot_instance);
         output_bytes("extaddr", (const uint8_t *)answer, OT_EXT_ADDRESS_SIZE);
@@ -172,6 +182,8 @@ OT_COMMAND ot_masterkey(otInstance* ot_instance, void* arg, void* answer) {
 }
 
 OT_COMMAND ot_mode(otInstance* ot_instance, void* arg, void* answer) {
+    (void)answer;
+
     if (arg != NULL) {
         otLinkModeConfig link_mode;
         memset(&link_mode, 0, sizeof(otLinkModeConfig));
@@ -233,6 +245,8 @@ OT_COMMAND ot_panid(otInstance* ot_instance, void* arg, void* answer) {
 }
 
 OT_COMMAND ot_parent(otInstance* ot_instance, void* arg, void* answer) {
+    (void)arg;
+
     if (answer != NULL) {
         otRouterInfo parentInfo;
         otThreadGetParentInfo(ot_instance, &parentInfo);
@@ -246,6 +260,8 @@ OT_COMMAND ot_parent(otInstance* ot_instance, void* arg, void* answer) {
 }
 
 OT_COMMAND ot_state(otInstance* ot_instance, void* arg, void* answer) {
+    (void)arg;
+
     if (answer != NULL) {
         uint8_t state = otThreadGetDeviceRole(ot_instance);
         *((uint8_t *) answer) = state;
@@ -280,6 +296,8 @@ OT_COMMAND ot_state(otInstance* ot_instance, void* arg, void* answer) {
 }
 
 OT_COMMAND ot_thread(otInstance* ot_instance, void* arg, void* answer) {
+    (void)answer;
+
     if (arg != NULL) {
         if (strcmp((char*)arg, "start") == 0) {
             otThreadSetEnabled(ot_instance, true);
diff --git a/pkg/openthread/contrib/platform_radio.c b/pkg/openthread/contrib/platform_radio.c
index 791c4a4a1c..27487e3670 100644
--- a/pkg/openthread/contrib/platform_radio.c
+++ b/pkg/openthread/contrib/platform_radio.c
@@ -132,8 +132,8 @@ void recv_pkt(otInstance *aInstance, netdev_t *dev)
     int len = dev->driver->recv(dev, NULL, 0, NULL);
 
     /* very unlikely */
-    if ((len > (unsigned) UINT16_MAX)) {
-        DEBUG("Len too high: %d\n", len);
+    if ((len < 0) || ((uint32_t)len > UINT16_MAX)) {
+        DEBUG("Invalid len: %d\n", len);
         otPlatRadioReceiveDone(aInstance, NULL, kThreadError_Abort);
         return;
     }
@@ -163,6 +163,8 @@ void recv_pkt(otInstance *aInstance, netdev_t *dev)
 /* Called upon TX event */
 void send_pkt(otInstance *aInstance, netdev_t *dev, netdev_event_t event)
 {
+    (void)dev;
+
     /* Tell OpenThread transmission is done depending on the NETDEV event */
     switch (event) {
         case NETDEV_EVENT_TX_COMPLETE:
@@ -189,6 +191,7 @@ void send_pkt(otInstance *aInstance, netdev_t *dev, netdev_event_t event)
 /* OpenThread will call this for setting PAN ID */
 void otPlatRadioSetPanId(otInstance *aInstance, uint16_t panid)
 {
+    (void)aInstance;
     DEBUG("openthread: otPlatRadioSetPanId: setting PAN ID to %04x\n", panid);
     _set_panid(panid);
 }
@@ -196,9 +199,10 @@ void otPlatRadioSetPanId(otInstance *aInstance, uint16_t panid)
 /* OpenThread will call this for setting extended address */
 void otPlatRadioSetExtendedAddress(otInstance *aInstance, uint8_t *aExtendedAddress)
 {
+    (void)aInstance;
     DEBUG("openthread: otPlatRadioSetExtendedAddress\n");
     uint8_t reversed_addr[IEEE802154_LONG_ADDRESS_LEN];
-    for (int i = 0; i < IEEE802154_LONG_ADDRESS_LEN; i++) {
+    for (unsigned i = 0; i < IEEE802154_LONG_ADDRESS_LEN; i++) {
         reversed_addr[i] = aExtendedAddress[IEEE802154_LONG_ADDRESS_LEN - 1 - i];
     }
     _set_long_addr(reversed_addr);
@@ -207,6 +211,7 @@ void otPlatRadioSetExtendedAddress(otInstance *aInstance, uint8_t *aExtendedAddr
 /* OpenThread will call this for setting short address */
 void otPlatRadioSetShortAddress(otInstance *aInstance, uint16_t aShortAddress)
 {
+    (void) aInstance;
     DEBUG("openthread: otPlatRadioSetShortAddress: setting address to %04x\n", aShortAddress);
     _set_addr(((aShortAddress & 0xff) << 8) | ((aShortAddress >> 8) & 0xff));
 }
@@ -275,6 +280,7 @@ ThreadError otPlatRadioReceive(otInstance *aInstance, uint8_t aChannel)
 /* OpenThread will call this function to get the transmit buffer */
 RadioPacket *otPlatRadioGetTransmitBuffer(otInstance *aInstance)
 {
+    (void) aInstance;
     DEBUG("openthread: otPlatRadioGetTransmitBuffer\n");
     return &sTransmitFrame;
 }
@@ -318,6 +324,7 @@ ThreadError otPlatRadioTransmit(otInstance *aInstance, RadioPacket *aPacket)
 /* OpenThread will call this for getting the radio caps */
 otRadioCaps otPlatRadioGetCaps(otInstance *aInstance)
 {
+    (void) aInstance;
     DEBUG("openthread: otPlatRadioGetCaps\n");
     /* all drivers should handle ACK, including call of NETDEV_EVENT_TX_NOACK */
     return kRadioCapsNone;
@@ -326,6 +333,7 @@ otRadioCaps otPlatRadioGetCaps(otInstance *aInstance)
 /* OpenThread will call this for getting the state of promiscuous mode */
 bool otPlatRadioGetPromiscuous(otInstance *aInstance)
 {
+    (void) aInstance;
     DEBUG("openthread: otPlatRadioGetPromiscuous\n");
     return _is_promiscuous();
 }
@@ -333,6 +341,7 @@ bool otPlatRadioGetPromiscuous(otInstance *aInstance)
 /* OpenThread will call this for setting the state of promiscuous mode */
 void otPlatRadioSetPromiscuous(otInstance *aInstance, bool aEnable)
 {
+    (void) aInstance;
     DEBUG("openthread: otPlatRadioSetPromiscuous\n");
     _set_promiscuous((aEnable) ? NETOPT_ENABLE : NETOPT_DISABLE);
 }
@@ -406,10 +415,12 @@ ThreadError otPlatRadioEnergyScan(otInstance *aInstance, uint8_t aScanChannel, u
 
 void otPlatRadioGetIeeeEui64(otInstance *aInstance, uint8_t *aIeee64Eui64)
 {
+    (void) aInstance;
     _dev->driver->get(_dev, NETOPT_IPV6_IID, aIeee64Eui64, sizeof(eui64_t));
 }
 
 int8_t otPlatRadioGetReceiveSensitivity(otInstance *aInstance)
 {
+    (void) aInstance;
     return -100;
 }
diff --git a/pkg/openthread/contrib/platform_settings.c b/pkg/openthread/contrib/platform_settings.c
index 0e324c5406..e95cea34ee 100644
--- a/pkg/openthread/contrib/platform_settings.c
+++ b/pkg/openthread/contrib/platform_settings.c
@@ -24,6 +24,7 @@
 
 void otPlatSettingsInit(otInstance *aInstance)
 {
+    (void)aInstance;
 }
 
 ThreadError otPlatSettingsBeginChange(otInstance *aInstance)
@@ -47,6 +48,11 @@ ThreadError otPlatSettingsAbandonChange(otInstance *aInstance)
 
 ThreadError otPlatSettingsGet(otInstance *aInstance, uint16_t aKey, int aIndex, uint8_t *aValue, uint16_t *aValueLength)
 {
+    (void)aInstance;
+    (void)aKey;
+    (void)aIndex;
+    (void)aValue;
+
     DEBUG("openthread: otPlatSettingsGet\n");
     *aValueLength = 0;
     return kThreadError_NotImplemented;
@@ -54,19 +60,34 @@ ThreadError otPlatSettingsGet(otInstance *aInstance, uint16_t aKey, int aIndex,
 
 ThreadError otPlatSettingsSet(otInstance *aInstance, uint16_t aKey, const uint8_t *aValue, uint16_t aValueLength)
 {
+    (void)aInstance;
+    (void)aKey;
+    (void)aValue;
+    (void)aValueLength;
+
     return kThreadError_None;
 }
 
 ThreadError otPlatSettingsAdd(otInstance *aInstance, uint16_t aKey, const uint8_t *aValue, uint16_t aValueLength)
 {
+    (void)aInstance;
+    (void)aKey;
+    (void)aValue;
+    (void)aValueLength;
+
     return kThreadError_None;
 }
 
 ThreadError otPlatSettingsDelete(otInstance *aInstance, uint16_t aKey, int aIndex)
 {
+    (void)aInstance;
+    (void)aKey;
+    (void)aIndex;
+
     return kThreadError_None;
 }
 
 void otPlatSettingsWipe(otInstance *aInstance)
 {
+    (void)aInstance;
 }
diff --git a/sys/auto_init/saul/auto_init_gpio.c b/sys/auto_init/saul/auto_init_gpio.c
index 6e34458ae6..ed98acf464 100644
--- a/sys/auto_init/saul/auto_init_gpio.c
+++ b/sys/auto_init/saul/auto_init_gpio.c
@@ -30,7 +30,15 @@
 /**
  * @brief   Define the number of configured sensors
  */
-#define SAUL_GPIO_NUMOF    (sizeof(saul_gpio_params)/sizeof(saul_gpio_params[0]))
+#if defined(SAUL_GPIO_NUMOF) && !(SAUL_GPIO_NUMOF > 0)
+void auto_init_gpio(void)
+{
+    /* do nothing, no GPIO configured for SAUL */
+    LOG_DEBUG("[auto_init_saul] no SAUL GPIO configured!\n");
+}
+#else
+#define SAUL_GPIO_NUMOF (sizeof(saul_gpio_params)/sizeof(saul_gpio_params[0]))
+
 
 /**
  * @brief   Memory for the registry entries
@@ -76,7 +84,7 @@ void auto_init_gpio(void)
         saul_reg_add(&(saul_reg_entries[i]));
     }
 }
-
+#endif
 #else
 typedef int dont_be_pedantic;
 #endif /* MODULE_SAUL_GPIO */
diff --git a/sys/include/xtimer/tick_conversion.h b/sys/include/xtimer/tick_conversion.h
index df989a2ce2..a4306cf58f 100644
--- a/sys/include/xtimer/tick_conversion.h
+++ b/sys/include/xtimer/tick_conversion.h
@@ -39,19 +39,19 @@ extern "C" {
 #endif
 /* XTIMER_HZ is a power-of-two multiple of 1 MHz */
 /* e.g. cc2538 uses a 16 MHz timer */
-inline static uint32_t _xtimer_ticks_from_usec(uint32_t usec) {
+static inline uint32_t _xtimer_ticks_from_usec(uint32_t usec) {
     return (usec << XTIMER_SHIFT); /* multiply by power of two */
 }
 
-inline static uint64_t _xtimer_ticks_from_usec64(uint64_t usec) {
+static inline uint64_t _xtimer_ticks_from_usec64(uint64_t usec) {
     return (usec << XTIMER_SHIFT); /* multiply by power of two */
 }
 
-inline static uint32_t _xtimer_usec_from_ticks(uint32_t ticks) {
+static inline uint32_t _xtimer_usec_from_ticks(uint32_t ticks) {
     return (ticks >> XTIMER_SHIFT); /* divide by power of two */
 }
 
-inline static uint64_t _xtimer_usec_from_ticks64(uint64_t ticks) {
+static inline uint64_t _xtimer_usec_from_ticks64(uint64_t ticks) {
     return (ticks >> XTIMER_SHIFT); /* divide by power of two */
 }
 
@@ -61,38 +61,38 @@ inline static uint64_t _xtimer_usec_from_ticks64(uint64_t ticks) {
 #endif
 /* 1 MHz is a power-of-two multiple of XTIMER_HZ */
 /* e.g. ATmega2560 uses a 250 kHz timer */
-inline static uint32_t _xtimer_ticks_from_usec(uint32_t usec) {
+static inline uint32_t _xtimer_ticks_from_usec(uint32_t usec) {
     return (usec >> XTIMER_SHIFT); /* divide by power of two */
 }
 
-inline static uint64_t _xtimer_ticks_from_usec64(uint64_t usec) {
+static inline uint64_t _xtimer_ticks_from_usec64(uint64_t usec) {
     return (usec >> XTIMER_SHIFT); /* divide by power of two */
 }
 
-inline static uint32_t _xtimer_usec_from_ticks(uint32_t ticks) {
+static inline uint32_t _xtimer_usec_from_ticks(uint32_t ticks) {
     return (ticks << XTIMER_SHIFT); /* multiply by power of two */
 }
 
-inline static uint64_t _xtimer_usec_from_ticks64(uint64_t ticks) {
+static inline uint64_t _xtimer_usec_from_ticks64(uint64_t ticks) {
     return (ticks << XTIMER_SHIFT); /* multiply by power of two */
 }
 #endif /* defined(XTIMER_SHIFT) && (XTIMER_SHIFT != 0) */
 #elif XTIMER_HZ == (1000000ul)
 /* This is the most straightforward as the xtimer API is based around
  * microseconds for representing time values. */
-inline static uint32_t _xtimer_usec_from_ticks(uint32_t ticks) {
+static inline uint32_t _xtimer_usec_from_ticks(uint32_t ticks) {
     return ticks; /* no-op */
 }
 
-inline static uint64_t _xtimer_usec_from_ticks64(uint64_t ticks) {
+static inline uint64_t _xtimer_usec_from_ticks64(uint64_t ticks) {
     return ticks; /* no-op */
 }
 
-inline static uint32_t _xtimer_ticks_from_usec(uint32_t usec) {
+static inline uint32_t _xtimer_ticks_from_usec(uint32_t usec) {
     return usec; /* no-op */
 }
 
-inline static uint64_t _xtimer_ticks_from_usec64(uint64_t usec) {
+static inline uint64_t _xtimer_ticks_from_usec64(uint64_t usec) {
     return usec; /* no-op */
 }
 
@@ -101,22 +101,22 @@ inline static uint64_t _xtimer_ticks_from_usec64(uint64_t usec) {
  * greatest common divisor between 32768 and 1000000 is 64, so instead of
  * multiplying by the fraction (32768 / 1000000), we will instead use
  * (512 / 15625), which reduces the truncation caused by the integer widths */
-inline static uint32_t _xtimer_ticks_from_usec(uint32_t usec) {
+static inline uint32_t _xtimer_ticks_from_usec(uint32_t usec) {
     return div_u32_by_15625div512(usec);
 }
 
-inline static uint64_t _xtimer_ticks_from_usec64(uint64_t usec) {
+static inline uint64_t _xtimer_ticks_from_usec64(uint64_t usec) {
     return div_u64_by_15625div512(usec);
 }
 
-inline static uint32_t _xtimer_usec_from_ticks(uint32_t ticks) {
+static inline uint32_t _xtimer_usec_from_ticks(uint32_t ticks) {
     /* return (usec * 15625) / 512; */
     /* Using 64 bit multiplication to avoid truncating the top 9 bits */
     uint64_t usec = (uint64_t)ticks * 15625ul;
     return (usec >> 9); /* equivalent to (usec / 512) */
 }
 
-inline static uint64_t _xtimer_usec_from_ticks64(uint64_t ticks) {
+static inline uint64_t _xtimer_usec_from_ticks64(uint64_t ticks) {
     /* return (usec * 15625) / 512; */
     uint64_t usec = (uint64_t)ticks * 15625ul;
     return (usec >> 9); /* equivalent to (usec / 512) */
diff --git a/sys/net/gnrc/netif/gnrc_netif.c b/sys/net/gnrc/netif/gnrc_netif.c
index fab8969809..eb9f5447e5 100644
--- a/sys/net/gnrc/netif/gnrc_netif.c
+++ b/sys/net/gnrc/netif/gnrc_netif.c
@@ -132,7 +132,7 @@ int gnrc_netif_get_from_netdev(gnrc_netif_t *netif, gnrc_netapi_opt_t *opt)
 
                 res = 0;
                 for (unsigned i = 0;
-                     (res < opt->data_len) && (i < GNRC_NETIF_IPV6_ADDRS_NUMOF);
+                     (res < (int)opt->data_len) && (i < GNRC_NETIF_IPV6_ADDRS_NUMOF);
                      i++) {
                     if (netif->ipv6.addrs_flags[i] != 0) {
                         memcpy(tgt, &netif->ipv6.addrs[i], sizeof(ipv6_addr_t));
@@ -148,7 +148,7 @@ int gnrc_netif_get_from_netdev(gnrc_netif_t *netif, gnrc_netapi_opt_t *opt)
 
                 res = 0;
                 for (unsigned i = 0;
-                     (res < opt->data_len) && (i < GNRC_NETIF_IPV6_ADDRS_NUMOF);
+                     (res < (int)opt->data_len) && (i < GNRC_NETIF_IPV6_ADDRS_NUMOF);
                      i++) {
                     if (netif->ipv6.addrs_flags[i] != 0) {
                         *tgt = netif->ipv6.addrs_flags[i];
@@ -164,7 +164,7 @@ int gnrc_netif_get_from_netdev(gnrc_netif_t *netif, gnrc_netapi_opt_t *opt)
 
                 res = 0;
                 for (unsigned i = 0;
-                     (res < opt->data_len) && (i < GNRC_NETIF_IPV6_GROUPS_NUMOF);
+                     (res < (int)opt->data_len) && (i < GNRC_NETIF_IPV6_GROUPS_NUMOF);
                      i++) {
                     if (!ipv6_addr_is_unspecified(&netif->ipv6.groups[i])) {
                         memcpy(tgt, &netif->ipv6.groups[i], sizeof(ipv6_addr_t));
diff --git a/sys/net/gnrc/network_layer/ipv6/nib/nib.c b/sys/net/gnrc/network_layer/ipv6/nib/nib.c
index 03403dc14f..0e39963af1 100644
--- a/sys/net/gnrc/network_layer/ipv6/nib/nib.c
+++ b/sys/net/gnrc/network_layer/ipv6/nib/nib.c
@@ -222,11 +222,11 @@ int gnrc_ipv6_nib_get_next_hop_l2addr(const ipv6_addr_t *dst,
                     break;
                 }
             }
-            if ((netif != NULL) && (netif->pid != route.iface)) {
+            if ((netif != NULL) && (netif->pid != (int)route.iface)) {
                 /* drop pre-assumed netif */
                 gnrc_netif_release(netif);
             }
-            if ((netif == NULL) || (netif->pid != route.iface)) {
+            if ((netif == NULL) || (netif->pid != (int)route.iface)) {
                 /* get actual netif */
                 netif = gnrc_netif_get_by_pid(route.iface);
                 gnrc_netif_acquire(netif);
diff --git a/sys/net/gnrc/network_layer/sixlowpan/iphc/gnrc_sixlowpan_iphc.c b/sys/net/gnrc/network_layer/sixlowpan/iphc/gnrc_sixlowpan_iphc.c
index 25087dc389..28df9ee0b8 100644
--- a/sys/net/gnrc/network_layer/sixlowpan/iphc/gnrc_sixlowpan_iphc.c
+++ b/sys/net/gnrc/network_layer/sixlowpan/iphc/gnrc_sixlowpan_iphc.c
@@ -111,7 +111,7 @@ static inline bool _context_overlaps_iid(gnrc_sixlowpan_ctx_t *ctx,
 }
 
 #ifdef MODULE_GNRC_SIXLOWPAN_IPHC_NHC
-inline static size_t iphc_nhc_udp_decode(gnrc_pktsnip_t *pkt, gnrc_pktsnip_t **dec_hdr,
+static inline size_t iphc_nhc_udp_decode(gnrc_pktsnip_t *pkt, gnrc_pktsnip_t **dec_hdr,
                                          size_t datagram_size, size_t offset)
 {
     uint8_t *payload = pkt->data;
@@ -520,7 +520,7 @@ size_t gnrc_sixlowpan_iphc_decode(gnrc_pktsnip_t **dec_hdr, gnrc_pktsnip_t *pkt,
 }
 
 #ifdef MODULE_GNRC_SIXLOWPAN_IPHC_NHC
-inline static size_t iphc_nhc_udp_encode(gnrc_pktsnip_t *udp, ipv6_hdr_t *ipv6_hdr)
+static inline size_t iphc_nhc_udp_encode(gnrc_pktsnip_t *udp, ipv6_hdr_t *ipv6_hdr)
 {
     udp_hdr_t *udp_hdr = udp->data;
     network_uint16_t *src_port = &(udp_hdr->src_port);
diff --git a/sys/net/gnrc/transport_layer/tcp/internal/option.h b/sys/net/gnrc/transport_layer/tcp/internal/option.h
index 2e611d9cdc..b49bf6913d 100644
--- a/sys/net/gnrc/transport_layer/tcp/internal/option.h
+++ b/sys/net/gnrc/transport_layer/tcp/internal/option.h
@@ -38,7 +38,7 @@ extern "C" {
  *
  * @returns   MSS option value.
  */
-inline static uint32_t _option_build_mss(uint16_t mss)
+static inline uint32_t _option_build_mss(uint16_t mss)
 {
     return (((uint32_t) TCP_OPTION_KIND_MSS << 24) |
             ((uint32_t) TCP_OPTION_LENGTH_MSS << 16) | mss);
@@ -52,7 +52,7 @@ inline static uint32_t _option_build_mss(uint16_t mss)
  *
  * @returns   Bitfield with encoded control bits and number of options.
  */
-inline static uint16_t _option_build_offset_control(uint16_t nopts, uint16_t ctl)
+static inline uint16_t _option_build_offset_control(uint16_t nopts, uint16_t ctl)
 {
     assert(TCP_HDR_OFFSET_MIN <= nopts && nopts <= TCP_HDR_OFFSET_MAX);
     return (nopts << 12) | ctl;
diff --git a/sys/pm_layered/pm.c b/sys/pm_layered/pm.c
index 132cc52fe6..8a0326a3bf 100644
--- a/sys/pm_layered/pm.c
+++ b/sys/pm_layered/pm.c
@@ -48,7 +48,7 @@ volatile pm_blocker_t pm_blocker = PM_BLOCKER_INITIAL;
 
 void pm_set_lowest(void)
 {
-    pm_blocker_t blocker = (pm_blocker_t) pm_blocker;
+    pm_blocker_t blocker = pm_blocker;
     unsigned mode = PM_NUM_MODES;
     while (mode) {
         if (blocker.val_u8[mode-1]) {
diff --git a/sys/posix/pthread/pthread_cond.c b/sys/posix/pthread/pthread_cond.c
index f03e4a9c0c..78354718b3 100644
--- a/sys/posix/pthread/pthread_cond.c
+++ b/sys/posix/pthread/pthread_cond.c
@@ -122,7 +122,7 @@ int pthread_cond_wait(pthread_cond_t *cond, mutex_t *mutex)
 
 int pthread_cond_timedwait(pthread_cond_t *cond, mutex_t *mutex, const struct timespec *abstime)
 {
-    if ((cond == NULL) || (abstime->tv_sec < 0)) {
+    if (cond == NULL) {
         return EINVAL;
     }
 
diff --git a/sys/random/tinymt32/tinymt32.h b/sys/random/tinymt32/tinymt32.h
index 87881b3950..3a5802518a 100644
--- a/sys/random/tinymt32/tinymt32.h
+++ b/sys/random/tinymt32/tinymt32.h
@@ -46,7 +46,7 @@ void tinymt32_init(tinymt32_t *random, uint32_t seed);
 void tinymt32_init_by_array(tinymt32_t *random, uint32_t init_key[],
                             int key_length);
 
-inline static int tinymt32_get_mexp(tinymt32_t *random)
+static inline int tinymt32_get_mexp(tinymt32_t *random)
 {
     (void) random;
     return TINYMT32_MEXP;
@@ -57,7 +57,7 @@ inline static int tinymt32_get_mexp(tinymt32_t *random)
  * Users should not call this function directly.
  * @param random tinymt internal status
  */
-inline static void tinymt32_next_state(tinymt32_t *random)
+static inline void tinymt32_next_state(tinymt32_t *random)
 {
     uint32_t x;
     uint32_t y;
@@ -82,7 +82,7 @@ inline static void tinymt32_next_state(tinymt32_t *random)
  * @param random tinymt internal status
  * @return 32-bit unsigned pseudorandom number
  */
-inline static uint32_t tinymt32_temper(tinymt32_t *random)
+static inline uint32_t tinymt32_temper(tinymt32_t *random)
 {
     uint32_t t0, t1;
 
@@ -99,7 +99,7 @@ inline static uint32_t tinymt32_temper(tinymt32_t *random)
  * @param random tinymt internal status
  * @return floating point number r (1.0 <= r < 2.0)
  */
-inline static float tinymt32_temper_conv(tinymt32_t *random)
+static inline float tinymt32_temper_conv(tinymt32_t *random)
 {
     uint32_t t0, t1;
 
@@ -122,7 +122,7 @@ inline static float tinymt32_temper_conv(tinymt32_t *random)
  * @param random tinymt internal status
  * @return floating point number r (1.0 < r < 2.0)
  */
-inline static float tinymt32_temper_conv_open(tinymt32_t *random)
+static inline float tinymt32_temper_conv_open(tinymt32_t *random)
 {
     uint32_t t0, t1;
 
@@ -144,7 +144,7 @@ inline static float tinymt32_temper_conv_open(tinymt32_t *random)
  * @param random tinymt internal status
  * @return 32-bit unsigned integer r (0 <= r < 2^32)
  */
-inline static uint32_t tinymt32_generate_uint32(tinymt32_t *random)
+static inline uint32_t tinymt32_generate_uint32(tinymt32_t *random)
 {
     tinymt32_next_state(random);
     return tinymt32_temper(random);
@@ -158,7 +158,7 @@ inline static uint32_t tinymt32_generate_uint32(tinymt32_t *random)
  * @param random tinymt internal status
  * @return floating point number r (0.0 <= r < 1.0)
  */
-inline static float tinymt32_generate_float(tinymt32_t *random)
+static inline float tinymt32_generate_float(tinymt32_t *random)
 {
     tinymt32_next_state(random);
     return (tinymt32_temper(random) >> 8) * TINYMT32_MUL;
@@ -170,7 +170,7 @@ inline static float tinymt32_generate_float(tinymt32_t *random)
  * @param random tinymt internal status
  * @return floating point number r (1.0 <= r < 2.0)
  */
-inline static float tinymt32_generate_float12(tinymt32_t *random)
+static inline float tinymt32_generate_float12(tinymt32_t *random)
 {
     tinymt32_next_state(random);
     return tinymt32_temper_conv(random);
@@ -182,7 +182,7 @@ inline static float tinymt32_generate_float12(tinymt32_t *random)
  * @param random tinymt internal status
  * @return floating point number r (0.0 <= r < 1.0)
  */
-inline static float tinymt32_generate_float01(tinymt32_t *random)
+static inline float tinymt32_generate_float01(tinymt32_t *random)
 {
     tinymt32_next_state(random);
     return tinymt32_temper_conv(random) - 1.0f;
@@ -194,7 +194,7 @@ inline static float tinymt32_generate_float01(tinymt32_t *random)
  * @param random tinymt internal status
  * @return floating point number r (0.0 < r <= 1.0)
  */
-inline static float tinymt32_generate_floatOC(tinymt32_t *random)
+static inline float tinymt32_generate_floatOC(tinymt32_t *random)
 {
     tinymt32_next_state(random);
     return 1.0f - tinymt32_generate_float(random);
@@ -206,7 +206,7 @@ inline static float tinymt32_generate_floatOC(tinymt32_t *random)
  * @param random tinymt internal status
  * @return floating point number r (0.0 < r < 1.0)
  */
-inline static float tinymt32_generate_floatOO(tinymt32_t *random)
+static inline float tinymt32_generate_floatOO(tinymt32_t *random)
 {
     tinymt32_next_state(random);
     return tinymt32_temper_conv_open(random) - 1.0f;
@@ -220,7 +220,7 @@ inline static float tinymt32_generate_floatOO(tinymt32_t *random)
  * @param random tinymt internal status
  * @return floating point number r (0.0 < r <= 1.0)
  */
-inline static double tinymt32_generate_32double(tinymt32_t *random)
+static inline double tinymt32_generate_32double(tinymt32_t *random)
 {
     tinymt32_next_state(random);
     return tinymt32_temper(random) * (1.0 / 4294967296.0);
diff --git a/sys/shell/commands/sc_gnrc_netif.c b/sys/shell/commands/sc_gnrc_netif.c
index 14d90444b7..a70e9797df 100644
--- a/sys/shell/commands/sc_gnrc_netif.c
+++ b/sys/shell/commands/sc_gnrc_netif.c
@@ -517,7 +517,7 @@ static void _netif_list(kernel_pid_t iface)
 static int _netif_set_u16(kernel_pid_t iface, netopt_t opt, uint16_t context,
                           char *u16_str)
 {
-    unsigned int res;
+    unsigned long int res;
     bool hex = false;
 
     if (_is_number(u16_str)) {
@@ -556,10 +556,10 @@ static int _netif_set_u16(kernel_pid_t iface, netopt_t opt, uint16_t context,
     printf(" on interface %" PRIkernel_pid " to ", iface);
 
     if (hex) {
-        printf("0x%04x\n", res);
+        printf("0x%04lx\n", res);
     }
     else {
-        printf("%u\n", res);
+        printf("%lu\n", res);
     }
 
     return 0;
diff --git a/sys/vfs/vfs.c b/sys/vfs/vfs.c
index 0217dd4fe3..a97ea1f678 100644
--- a/sys/vfs/vfs.c
+++ b/sys/vfs/vfs.c
@@ -75,7 +75,7 @@ static clist_node_t _vfs_mounts_list;
  * @return fd on success
  * @return <0 on error
  */
-inline static int _allocate_fd(int fd);
+static inline int _allocate_fd(int fd);
 
 /**
  * @internal
@@ -83,7 +83,7 @@ inline static int _allocate_fd(int fd);
  *
  * @param[in]  fd     fd to free
  */
-inline static void _free_fd(int fd);
+static inline void _free_fd(int fd);
 
 /**
  * @internal
@@ -98,7 +98,7 @@ inline static void _free_fd(int fd);
  * @return fd on success
  * @return <0 on error
  */
-inline static int _init_fd(int fd, const vfs_file_ops_t *f_op, vfs_mount_t *mountp, int flags, void *private_data);
+static inline int _init_fd(int fd, const vfs_file_ops_t *f_op, vfs_mount_t *mountp, int flags, void *private_data);
 
 /**
  * @internal
@@ -115,7 +115,7 @@ inline static int _init_fd(int fd, const vfs_file_ops_t *f_op, vfs_mount_t *moun
  * @return mount index on success
  * @return <0 on error
  */
-inline static int _find_mount(vfs_mount_t **mountpp, const char *name, const char **rel_path);
+static inline int _find_mount(vfs_mount_t **mountpp, const char *name, const char **rel_path);
 
 /**
  * @internal
@@ -126,7 +126,7 @@ inline static int _find_mount(vfs_mount_t **mountpp, const char *name, const cha
  * @return 0 if the fd is valid
  * @return <0 if the fd is not valid
  */
-inline static int _fd_is_valid(int fd);
+static inline int _fd_is_valid(int fd);
 
 static mutex_t _mount_mutex = MUTEX_INIT;
 static mutex_t _open_mutex = MUTEX_INIT;
@@ -810,7 +810,7 @@ const vfs_mount_t *vfs_iterate_mounts(const vfs_mount_t *cur)
     return container_of(node, vfs_mount_t, list_entry);
 }
 
-inline static int _allocate_fd(int fd)
+static inline int _allocate_fd(int fd)
 {
     if (fd < 0) {
         for (fd = 0; fd < VFS_MAX_OPEN_FILES; ++fd) {
@@ -837,7 +837,7 @@ inline static int _allocate_fd(int fd)
     return fd;
 }
 
-inline static void _free_fd(int fd)
+static inline void _free_fd(int fd)
 {
     DEBUG("_free_fd: %d, pid=%d\n", fd, _vfs_open_files[fd].pid);
     if (_vfs_open_files[fd].mp != NULL) {
@@ -846,7 +846,7 @@ inline static void _free_fd(int fd)
     _vfs_open_files[fd].pid = KERNEL_PID_UNDEF;
 }
 
-inline static int _init_fd(int fd, const vfs_file_ops_t *f_op, vfs_mount_t *mountp, int flags, void *private_data)
+static inline int _init_fd(int fd, const vfs_file_ops_t *f_op, vfs_mount_t *mountp, int flags, void *private_data)
 {
     fd = _allocate_fd(fd);
     if (fd < 0) {
@@ -861,7 +861,7 @@ inline static int _init_fd(int fd, const vfs_file_ops_t *f_op, vfs_mount_t *moun
     return fd;
 }
 
-inline static int _find_mount(vfs_mount_t **mountpp, const char *name, const char **rel_path)
+static inline int _find_mount(vfs_mount_t **mountpp, const char *name, const char **rel_path)
 {
     size_t longest_match = 0;
     size_t name_len = strlen(name);
@@ -914,7 +914,7 @@ inline static int _find_mount(vfs_mount_t **mountpp, const char *name, const cha
     return 0;
 }
 
-inline static int _fd_is_valid(int fd)
+static inline int _fd_is_valid(int fd)
 {
     if ((unsigned int)fd >= VFS_MAX_OPEN_FILES) {
         return -EBADF;
diff --git a/tests/emb6/Makefile b/tests/emb6/Makefile
index b7b7fb337e..c21c820850 100644
--- a/tests/emb6/Makefile
+++ b/tests/emb6/Makefile
@@ -39,4 +39,7 @@ DRIVER ?= at86rf231
 # include the selected driver
 USEMODULE += $(DRIVER)
 
+CFLAGS += -Wno-unused-parameter -Wno-unused-function -Wno-type-limits
+CFLAGS += -Wno-sign-compare -Wno-missing-field-initializers
+
 include $(RIOTBASE)/Makefile.include
diff --git a/tests/pthread_cooperation/main.c b/tests/pthread_cooperation/main.c
index 8ab28ad522..b12357de16 100644
--- a/tests/pthread_cooperation/main.c
+++ b/tests/pthread_cooperation/main.c
@@ -28,7 +28,7 @@
 pthread_t ths[NUM_THREADS];
 
 pthread_mutex_t mtx;
-volatile int storage = 1;
+volatile uint32_t storage = 1;
 
 void *run(void *parameter)
 {
@@ -43,7 +43,7 @@ void *run(void *parameter)
     }
 
     storage *= arg;
-    printf("val = %d\n", storage);
+    printf("val = %"PRIu32"\n", storage);
     pthread_mutex_unlock(&mtx);
 
     return NULL;
@@ -66,7 +66,7 @@ int main(void)
         pthread_join(ths[i], NULL);
     }
 
-    printf("Factorial: %d\n", storage);
+    printf("Factorial: %"PRIu32"\n", storage);
 
     pthread_mutex_destroy(&mtx);
     pthread_attr_destroy(&th_attr);
diff --git a/tests/trickle/main.c b/tests/trickle/main.c
index 9ead2fde64..4a90e94aa5 100644
--- a/tests/trickle/main.c
+++ b/tests/trickle/main.c
@@ -53,14 +53,16 @@ static void callback(void *args)
     return;
 }
 
-static trickle_t trickle = { .callback.func = &callback,
-                             .callback.args = NULL };
+static trickle_t trickle;
 
 int main(void)
 {
     msg_t msg;
     unsigned counter = 0;
 
+    trickle.callback.func = &callback;
+    trickle.callback.args = NULL;
+
     trickle_start(sched_active_pid, &trickle, TRICKLE_MSG, TR_IMIN,
                   TR_IDOUBLINGS, TR_REDCONST);