diff --git a/boards/common/silabs/board_common.c b/boards/common/silabs/board_common.c
index 94864a9848..e187265645 100644
--- a/boards/common/silabs/board_common.c
+++ b/boards/common/silabs/board_common.c
@@ -20,9 +20,15 @@
 
 #include "board_common.h"
 
+#ifdef MODULE_SILABS_AEM
 #include "aem.h"
+#endif
+#ifdef MODULE_SILABS_BC
 #include "bc.h"
+#endif
+#ifdef MODULE_SILABS_PIC
 #include "pic.h"
+#endif
 
 void board_common_init(void)
 {
diff --git a/boards/ikea-tradfri/Makefile.dep b/boards/ikea-tradfri/Makefile.dep
index eba4fe3046..7a8feb2f81 100644
--- a/boards/ikea-tradfri/Makefile.dep
+++ b/boards/ikea-tradfri/Makefile.dep
@@ -1,5 +1,5 @@
 ifneq (,$(filter saul_default,$(USEMODULE)))
-    USEMODULE += saul_gpio
+  USEMODULE += saul_gpio
 endif
 
 include $(RIOTCPU)/efm32/Makefile.dep
diff --git a/boards/ikea-tradfri/Makefile.features b/boards/ikea-tradfri/Makefile.features
index 904f1df7b9..1006ab232b 100644
--- a/boards/ikea-tradfri/Makefile.features
+++ b/boards/ikea-tradfri/Makefile.features
@@ -9,4 +9,4 @@ FEATURES_PROVIDED += periph_uart
 # The board MPU family (used for grouping by the CI system)
 FEATURES_MCU_GROUP = cortex_m4_2
 
-include $(RIOTCPU)/efm32/Makefile.features
+-include $(RIOTCPU)/efm32/Makefile.features
diff --git a/boards/ikea-tradfri/include/board.h b/boards/ikea-tradfri/include/board.h
index ffb784a3fa..8292d7dc21 100644
--- a/boards/ikea-tradfri/include/board.h
+++ b/boards/ikea-tradfri/include/board.h
@@ -22,7 +22,6 @@
 #define BOARD_H
 
 #include "cpu.h"
-
 #include "periph_conf.h"
 #include "periph/gpio.h"
 #include "periph/spi.h"
diff --git a/boards/ikea-tradfri/include/periph_conf.h b/boards/ikea-tradfri/include/periph_conf.h
index 54987ab063..0af367fd21 100644
--- a/boards/ikea-tradfri/include/periph_conf.h
+++ b/boards/ikea-tradfri/include/periph_conf.h
@@ -20,9 +20,7 @@
 #define PERIPH_CONF_H
 
 #include "cpu.h"
-
 #include "periph_cpu.h"
-
 #include "em_cmu.h"
 
 #ifdef __cplusplus
diff --git a/boards/slstk3401a/board.c b/boards/slstk3401a/board.c
index cde723bfae..37313bb027 100644
--- a/boards/slstk3401a/board.c
+++ b/boards/slstk3401a/board.c
@@ -31,7 +31,7 @@ void board_init(void)
     /* perform common board initialization */
     board_common_init();
 
-#ifdef MODULE_SI70XX
+#ifdef MODULE_SI7021
     /* initialize the Si7021 sensor */
     gpio_init(SI7021_EN_PIN, GPIO_OUT);
     gpio_set(SI7021_EN_PIN);
diff --git a/boards/sltb001a/Makefile.dep b/boards/sltb001a/Makefile.dep
index ba9ffda054..7eab2e2f7a 100644
--- a/boards/sltb001a/Makefile.dep
+++ b/boards/sltb001a/Makefile.dep
@@ -1,7 +1,7 @@
 ifneq (,$(filter saul_default,$(USEMODULE)))
-    USEMODULE += saul_gpio
-    USEMODULE += bmp280
-    USEMODULE += si7021
+  USEMODULE += saul_gpio
+  USEMODULE += bmp280
+  USEMODULE += si7021
 endif
 
 # include board common dependencies
diff --git a/boards/sltb001a/Makefile.features b/boards/sltb001a/Makefile.features
index 6b5068bb24..eec9ddfd7d 100644
--- a/boards/sltb001a/Makefile.features
+++ b/boards/sltb001a/Makefile.features
@@ -11,4 +11,4 @@ FEATURES_PROVIDED += periph_uart
 # The board MPU family (used for grouping by the CI system)
 FEATURES_MCU_GROUP = cortex_m4_2
 
-include $(RIOTCPU)/efm32/Makefile.features
+-include $(RIOTCPU)/efm32/Makefile.features
diff --git a/boards/sltb001a/board.c b/boards/sltb001a/board.c
index a53862753c..26bde761d8 100644
--- a/boards/sltb001a/board.c
+++ b/boards/sltb001a/board.c
@@ -21,10 +21,12 @@
 
 #include "board.h"
 #include "board_common.h"
-#include "pic.h"
-
 #include "periph/gpio.h"
 
+#ifdef MODULE_SILABS_PIC
+#include "pic.h"
+#endif
+
 void board_init(void)
 {
     /* initialize the CPU */
@@ -34,23 +36,23 @@ void board_init(void)
     board_common_init();
 
 #ifdef MODULE_SILABS_PIC
-    /* enable the CCS811 air quality/gas sensor */
 #if CCS811_ENABLED
+    /* enable the CCS811 air quality/gas sensor */
     pic_write(CCS811_PIC_ADDR, (1 << CCS811_PIC_EN_BIT) | (1 << CCS811_PIC_WAKE_BIT));
 #endif
 
-    /* enable the IMU sensor */
 #if ICM_20648_ENABLED
+    /* enable the IMU sensor */
     pic_write(ICM20648_PIC_ADDR, 1 << ICM20648_PIC_EN_BIT);
 #endif
 
+#if defined(MODULE_BMP280) || defined(MODULE_SI7021) || SI1133_ENABLED || SI7210A_ENABLED
     /* enable the environmental sensors */
-#if BMP280_ENABLED || SI1133_ENABLED || SI7021_ENABLED || SI7210A_ENABLED
     pic_write(ENV_SENSE_PIC_ADDR, 1 << ENV_SENSE_PIC_BIT);
 #endif
 
-    /* enable the RGB leds */
 #if RGB_LED1_ENABLED || RGB_LED2_ENABLED || RGB_LED3_ENABLED || RGB_LED4_ENABLED
+    /* enable the RGB leds */
     pic_write(RGB_LED_ADDR,
               (1 << RGB_LED_EN_BIT) |
               (RGB_LED1_ENABLED << RGB_LED1_EN_BIT) |
diff --git a/boards/sltb001a/include/board.h b/boards/sltb001a/include/board.h
index 4fd5322b97..b398b623b6 100644
--- a/boards/sltb001a/include/board.h
+++ b/boards/sltb001a/include/board.h
@@ -23,7 +23,6 @@
 #define BOARD_H
 
 #include "cpu.h"
-
 #include "periph_conf.h"
 #include "periph/gpio.h"
 #include "periph/spi.h"
@@ -86,9 +85,6 @@ extern "C" {
  * Connection to the on-board pressure sensor (BMP280).
  * @{
  */
-#ifndef BMP280_ENABLED
-#define BMP280_ENABLED          (1)
-#endif
 #define BMP280_I2C              I2C_DEV(0)
 
 #define BMX280_PARAM_I2C_DEV    BMP280_I2C
@@ -178,9 +174,6 @@ extern "C" {
  * Connection to the on-board temperature/humidity sensor (Si7021).
  * @{
  */
-#ifndef SI7021_ENABLED
-#define SI7021_ENABLED          (1)
-#endif
 #define SI7021_I2C              I2C_DEV(0)
 
 #define SI70XX_PARAM_I2C_DEV    SI7021_I2C
diff --git a/boards/sltb001a/include/periph_conf.h b/boards/sltb001a/include/periph_conf.h
index b54d77f406..552a786418 100644
--- a/boards/sltb001a/include/periph_conf.h
+++ b/boards/sltb001a/include/periph_conf.h
@@ -21,9 +21,7 @@
 #define PERIPH_CONF_H
 
 #include "cpu.h"
-
 #include "periph_cpu.h"
-
 #include "em_cmu.h"
 
 #ifdef __cplusplus
diff --git a/boards/stk3600/Makefile.dep b/boards/stk3600/Makefile.dep
index db6255ce96..6821288802 100644
--- a/boards/stk3600/Makefile.dep
+++ b/boards/stk3600/Makefile.dep
@@ -1,5 +1,5 @@
 ifneq (,$(filter saul_default,$(USEMODULE)))
-    USEMODULE += saul_gpio
+  USEMODULE += saul_gpio
 endif
 
 # include board common dependencies
diff --git a/boards/stk3600/Makefile.features b/boards/stk3600/Makefile.features
index 6872fee4e2..bff358e352 100644
--- a/boards/stk3600/Makefile.features
+++ b/boards/stk3600/Makefile.features
@@ -13,4 +13,4 @@ FEATURES_PROVIDED += periph_uart
 # The board MPU family (used for grouping by the CI system)
 FEATURES_MCU_GROUP = cortex_m3_2
 
-include $(RIOTCPU)/efm32/Makefile.features
+-include $(RIOTCPU)/efm32/Makefile.features
diff --git a/boards/stk3600/include/board.h b/boards/stk3600/include/board.h
index 50a6c1bc04..0ecc3e3d06 100644
--- a/boards/stk3600/include/board.h
+++ b/boards/stk3600/include/board.h
@@ -23,7 +23,6 @@
 #define BOARD_H
 
 #include "cpu.h"
-
 #include "periph_conf.h"
 #include "periph/gpio.h"
 #include "periph/spi.h"
diff --git a/boards/stk3600/include/periph_conf.h b/boards/stk3600/include/periph_conf.h
index 4a29d9ef9f..accf1d2d89 100644
--- a/boards/stk3600/include/periph_conf.h
+++ b/boards/stk3600/include/periph_conf.h
@@ -21,9 +21,7 @@
 #define PERIPH_CONF_H
 
 #include "cpu.h"
-
 #include "periph_cpu.h"
-
 #include "em_cmu.h"
 
 #ifdef __cplusplus
diff --git a/boards/stk3700/Makefile.dep b/boards/stk3700/Makefile.dep
index db6255ce96..6821288802 100644
--- a/boards/stk3700/Makefile.dep
+++ b/boards/stk3700/Makefile.dep
@@ -1,5 +1,5 @@
 ifneq (,$(filter saul_default,$(USEMODULE)))
-    USEMODULE += saul_gpio
+  USEMODULE += saul_gpio
 endif
 
 # include board common dependencies
diff --git a/boards/stk3700/Makefile.features b/boards/stk3700/Makefile.features
index 6872fee4e2..bff358e352 100644
--- a/boards/stk3700/Makefile.features
+++ b/boards/stk3700/Makefile.features
@@ -13,4 +13,4 @@ FEATURES_PROVIDED += periph_uart
 # The board MPU family (used for grouping by the CI system)
 FEATURES_MCU_GROUP = cortex_m3_2
 
-include $(RIOTCPU)/efm32/Makefile.features
+-include $(RIOTCPU)/efm32/Makefile.features
diff --git a/boards/stk3700/include/board.h b/boards/stk3700/include/board.h
index 403afc6b80..26644197f8 100644
--- a/boards/stk3700/include/board.h
+++ b/boards/stk3700/include/board.h
@@ -23,7 +23,6 @@
 #define BOARD_H
 
 #include "cpu.h"
-
 #include "periph_conf.h"
 #include "periph/gpio.h"
 #include "periph/spi.h"
diff --git a/boards/stk3700/include/periph_conf.h b/boards/stk3700/include/periph_conf.h
index 2babb66454..dd0440e59f 100644
--- a/boards/stk3700/include/periph_conf.h
+++ b/boards/stk3700/include/periph_conf.h
@@ -21,9 +21,7 @@
 #define PERIPH_CONF_H
 
 #include "cpu.h"
-
 #include "periph_cpu.h"
-
 #include "em_cmu.h"
 
 #ifdef __cplusplus