diff --git a/drivers/at86rf215/at86rf215_netdev.c b/drivers/at86rf215/at86rf215_netdev.c
index 58b1b02f95..5e0baf8754 100644
--- a/drivers/at86rf215/at86rf215_netdev.c
+++ b/drivers/at86rf215/at86rf215_netdev.c
@@ -158,8 +158,8 @@ static int _send(netdev_t *netdev, const iolist_t *iolist)
 
         /* current packet data + FCS too long */
         if ((len + iol->iol_len + IEEE802154_FCS_LEN) > AT86RF215_MAX_PKT_LENGTH) {
-            DEBUG("[at86rf215] error: packet too large (%u byte) to be send\n",
-                  (unsigned)len + IEEE802154_FCS_LEN);
+            DEBUG("[at86rf215] error: packet too large (%" PRIuSIZE
+                  " byte) to be send\n", len + IEEE802154_FCS_LEN);
             at86rf215_tx_abort(dev);
             return -EOVERFLOW;
         }
diff --git a/drivers/at86rf2xx/at86rf2xx_netdev.c b/drivers/at86rf2xx/at86rf2xx_netdev.c
index 3767223cda..122f92eebf 100644
--- a/drivers/at86rf2xx/at86rf2xx_netdev.c
+++ b/drivers/at86rf2xx/at86rf2xx_netdev.c
@@ -30,6 +30,7 @@
 #include <assert.h>
 #include <errno.h>
 
+#include "architecture.h"
 #include "iolist.h"
 
 #include "net/eui64.h"
@@ -216,8 +217,8 @@ static int _send(netdev_t *netdev, const iolist_t *iolist)
     for (const iolist_t *iol = iolist; iol; iol = iol->iol_next) {
         /* current packet data + FCS too long */
         if ((len + iol->iol_len + 2) > AT86RF2XX_MAX_PKT_LENGTH) {
-            DEBUG("[at86rf2xx] error: packet too large (%u byte) to be send\n",
-                  (unsigned)len + 2);
+            DEBUG("[at86rf2xx] error: packet too large (%" PRIuSIZE
+                  " byte) to be send\n", len + 2);
             return -EOVERFLOW;
         }
         if (iol->iol_len) {
diff --git a/drivers/cc110x/cc110x_netdev.c b/drivers/cc110x/cc110x_netdev.c
index 5d66fc856a..3c686fe92d 100644
--- a/drivers/cc110x/cc110x_netdev.c
+++ b/drivers/cc110x/cc110x_netdev.c
@@ -425,10 +425,9 @@ static int cc110x_send(netdev_t *netdev, const iolist_t *iolist)
         if (iol->iol_len) {
             if (size + iol->iol_len > CC110X_MAX_FRAME_SIZE) {
                 cc110x_release(dev);
-                DEBUG("[cc110x] netdev_driver_t::send(): Frame size of %uB "
-                      "exceeds maximum supported size of %uB\n",
-                      (unsigned)(size + iol->iol_len),
-                      (unsigned)CC110X_MAX_FRAME_SIZE);
+                DEBUG("[cc110x] netdev_driver_t::send(): Frame size of %"
+                      PRIuSIZE "B exceeds maximum supported size of %uB\n",
+                      size + iol->iol_len, (unsigned)CC110X_MAX_FRAME_SIZE);
                 return -1;
             }
             memcpy(dev->buf.data + size, iol->iol_base, iol->iol_len);
diff --git a/drivers/cc1xxx_common/gnrc_netif_cc1xxx.c b/drivers/cc1xxx_common/gnrc_netif_cc1xxx.c
index 4a328978a2..f12149d447 100644
--- a/drivers/cc1xxx_common/gnrc_netif_cc1xxx.c
+++ b/drivers/cc1xxx_common/gnrc_netif_cc1xxx.c
@@ -120,7 +120,7 @@ static int cc1xxx_adpt_send(gnrc_netif_t *netif, gnrc_pktsnip_t *pkt)
 
     /* get the payload size and the dst address details */
     size = gnrc_pkt_len(pkt->next);
-    DEBUG("[cc1xxx-gnrc] send: payload of packet is %i\n", (int)size);
+    DEBUG("[cc1xxx-gnrc] send: payload of packet is %" PRIuSIZE "\n", size);
     netif_hdr = (gnrc_netif_hdr_t *)pkt->data;
 
     l2hdr.src_addr = cc1xxx_dev->addr;
diff --git a/drivers/cc2420/cc2420.c b/drivers/cc2420/cc2420.c
index d190be3546..037d4c3d34 100644
--- a/drivers/cc2420/cc2420.c
+++ b/drivers/cc2420/cc2420.c
@@ -133,7 +133,7 @@ size_t cc2420_tx_prepare(cc2420_t *dev, const iolist_t *iolist)
             cc2420_fifo_write(dev, iol->iol_base, iol->iol_len);
         }
     }
-    DEBUG("cc2420: tx_prep: loaded %i byte into the TX FIFO\n", (int)pkt_len);
+    DEBUG("cc2420: tx_prep: loaded %" PRIuSIZE " byte into the TX FIFO\n", pkt_len);
 
     return pkt_len;
 }
diff --git a/drivers/dose/dose.c b/drivers/dose/dose.c
index b8ea8c0355..17a43dc6dd 100644
--- a/drivers/dose/dose.c
+++ b/drivers/dose/dose.c
@@ -443,7 +443,7 @@ static int _recv(netdev_t *dev, void *buf, size_t len, void *info)
 
     size_t dummy;
     if (crb_get_chunk_size(&ctx->rb, &dummy)) {
-        DEBUG("dose: %u byte pkt in rx queue\n", (unsigned)dummy);
+        DEBUG("dose: %" PRIuSIZE " byte pkt in rx queue\n", dummy);
         netdev_trigger_event_isr(&ctx->netdev);
     }
 
diff --git a/drivers/enc28j60/enc28j60.c b/drivers/enc28j60/enc28j60.c
index 22b626d1f7..17fb3f7503 100644
--- a/drivers/enc28j60/enc28j60.c
+++ b/drivers/enc28j60/enc28j60.c
@@ -330,8 +330,8 @@ static int nd_recv(netdev_t *netdev, void *buf, size_t max_len, void *info)
     next = (uint16_t)((head[1] << 8) | head[0]);
     size = (uint16_t)((head[3] << 8) | head[2]) - 4;  /* discard CRC */
 
-    DEBUG("[enc28j60] recv: size=%i next=%i buf=%p len=%d\n",
-          (int)size, (int)next, buf, max_len);
+    DEBUG("[enc28j60] recv: size=%u next=%u buf=%p len=%" PRIuSIZE "\n",
+          size, next, buf, max_len);
 
     if (buf != NULL) {
         /* read packet content into the supplied buffer */
diff --git a/drivers/kw41zrf/kw41zrf_netdev.c b/drivers/kw41zrf/kw41zrf_netdev.c
index c8910b1bba..51a8e650f4 100644
--- a/drivers/kw41zrf/kw41zrf_netdev.c
+++ b/drivers/kw41zrf/kw41zrf_netdev.c
@@ -243,14 +243,14 @@ static int kw41zrf_netdev_send(netdev_t *netdev, const iolist_t *iolist)
     for (const iolist_t *iol = iolist; iol; iol = iol->iol_next) {
         /* current packet data + FCS too long */
         if ((len + iol->iol_len) > (KW41ZRF_MAX_PKT_LENGTH - IEEE802154_FCS_LEN)) {
-            LOG_ERROR("[kw41zrf] packet too large (%u byte) to fit\n",
-                  (unsigned)len + IEEE802154_FCS_LEN);
+            LOG_ERROR("[kw41zrf] packet too large (%" PRIuSIZE " byte) to fit\n",
+                  len + IEEE802154_FCS_LEN);
             return -EOVERFLOW;
         }
         len = kw41zrf_tx_load(iol->iol_base, iol->iol_len, len);
     }
 
-    DEBUG("[kw41zrf] TX %u bytes\n", len);
+    DEBUG("[kw41zrf] TX %" PRIuSIZE " bytes\n", len);
 
     /*
      * First octet in the TX buffer contains the frame length.
diff --git a/drivers/lcd/lcd.c b/drivers/lcd/lcd.c
index b6a89333f2..d520f3bb96 100644
--- a/drivers/lcd/lcd.c
+++ b/drivers/lcd/lcd.c
@@ -428,8 +428,8 @@ void lcd_pixmap(lcd_t *dev, uint16_t x1, uint16_t x2,
     size_t num_pix = (x2 - x1 + 1) * (y2 - y1 + 1);
 
     DEBUG("[lcd]: Write x1: %" PRIu16 ", x2: %" PRIu16 ", "
-          "y1: %" PRIu16 ", y2: %" PRIu16 ". Num pixels: %lu\n",
-          x1, x2, y1, y2, (unsigned long)num_pix);
+          "y1: %" PRIu16 ", y2: %" PRIu16 ". Num pixels: %" PRIuSIZE "\n",
+          x1, x2, y1, y2, num_pix);
 
     lcd_ll_acquire(dev);
 
diff --git a/drivers/usbdev_mock/usbdev_mock.c b/drivers/usbdev_mock/usbdev_mock.c
index 944cef9381..ea3751f2cc 100644
--- a/drivers/usbdev_mock/usbdev_mock.c
+++ b/drivers/usbdev_mock/usbdev_mock.c
@@ -17,6 +17,7 @@
 #include <stdio.h>
 #include <string.h>
 
+#include "architecture.h"
 #include "periph/usbdev.h"
 #include "test_utils/expect.h"
 #include "usbdev_mock.h"
@@ -200,8 +201,8 @@ void _ep_esr(usbdev_ep_t *ep)
 
 int _xmit(usbdev_ep_t *ep, uint8_t *buf, size_t len)
 {
-    DEBUG("[mock]: Readying EP %u, dir %s, len %u\n",
-          ep->num, ep->dir == USB_EP_DIR_OUT ? "out" : "in", (unsigned)len);
+    DEBUG("[mock]: Readying EP %u, dir %s, len %" PRIuSIZE "\n",
+          ep->num, ep->dir == USB_EP_DIR_OUT ? "out" : "in", len);
     if (ep->num == 0) {
         usbdev_mock_t *usbdev_mock = _ep2dev(ep);
         usbdev_mock_ep_t *mock_ep = (usbdev_mock_ep_t *)ep;
diff --git a/drivers/xbee/gnrc_xbee.c b/drivers/xbee/gnrc_xbee.c
index 27a32f9aca..a0173e1529 100644
--- a/drivers/xbee/gnrc_xbee.c
+++ b/drivers/xbee/gnrc_xbee.c
@@ -111,7 +111,7 @@ static int xbee_adpt_send(gnrc_netif_t *netif, gnrc_pktsnip_t *pkt)
 
     /* get the payload size and the dst address details */
     size = gnrc_pkt_len(pkt->next);
-    DEBUG("[xbee-gnrc] send: payload of packet is %i\n", (int)size);
+    DEBUG("[xbee-gnrc] send: payload of packet is %" PRIuSIZE "\n", size);
     hdr = (gnrc_netif_hdr_t *)pkt->data;
     if (hdr->flags & BCAST) {
         uint16_t addr = 0xffff;
diff --git a/drivers/xbee/xbee.c b/drivers/xbee/xbee.c
index 7dcbb718d9..a71cdba7c5 100644
--- a/drivers/xbee/xbee.c
+++ b/drivers/xbee/xbee.c
@@ -673,7 +673,7 @@ static int xbee_send(netdev_t *dev, const iolist_t *iolist)
     }
 
     /* send the actual data packet */
-    DEBUG("[xbee] send: now sending out %i byte\n", (int)size);
+    DEBUG("[xbee] send: now sending out %" PRIuSIZE " byte\n", size);
     mutex_lock(&(xbee->tx_lock));
     for (const iolist_t *iol = iolist; iol; iol = iol->iol_next) {
         if (iol->iol_len > 0) {
@@ -705,16 +705,16 @@ static int xbee_recv(netdev_t *dev, void *buf, size_t len, void *info)
     size = (size_t)(xbee->rx_limit - 1);
     if (buf == NULL) {
         if (len > 0) {
-            DEBUG("[xbee] recv: reading size and dropping: %u\n", (unsigned)size);
+            DEBUG("[xbee] recv: reading size and dropping: %" PRIuSIZE "\n", size);
             xbee->rx_count = 0;
         }
         else {
-            DEBUG("[xbee] recv: reading size without dropping: %u\n", (unsigned)size);
+            DEBUG("[xbee] recv: reading size without dropping: %" PRIuSIZE "\n", size);
         }
     }
     else {
         size = (size > len) ? len : size;
-        DEBUG("[xbee] recv: consuming packet: reading %u byte\n", (unsigned)size);
+        DEBUG("[xbee] recv: consuming packet: reading %" PRIuSIZE " byte\n", size);
         memcpy(buf, xbee->rx_buf, size);
         xbee->rx_count = 0;
     }