diff --git a/core/net/mac/framer-802154.c b/core/net/mac/framer-802154.c
index c7e4b50c2..a0aea598b 100644
--- a/core/net/mac/framer-802154.c
+++ b/core/net/mac/framer-802154.c
@@ -132,7 +132,7 @@ create_frame(int type, int do_create)
      \todo For phase 1 the addresses are all long. We'll need a mechanism
      in the rime attributes to tell the mac to use long or short for phase 2.
   */
-  if(sizeof(linkaddr_t) == 2) {
+  if(LINKADDR_SIZE == 2) {
     /* Use short address mode if linkaddr size is short. */
     params.fcf.src_addr_mode = FRAME802154_SHORTADDRMODE;
   } else {
@@ -154,7 +154,7 @@ create_frame(int type, int do_create)
     linkaddr_copy((linkaddr_t *)&params.dest_addr,
                   packetbuf_addr(PACKETBUF_ADDR_RECEIVER));
     /* Use short address mode if linkaddr size is small */
-    if(sizeof(linkaddr_t) == 2) {
+    if(LINKADDR_SIZE == 2) {
       params.fcf.dest_addr_mode = FRAME802154_SHORTADDRMODE;
     } else {
       params.fcf.dest_addr_mode = FRAME802154_LONGADDRMODE;
diff --git a/core/net/packetbuf.h b/core/net/packetbuf.h
index fe2c1dae3..ab84da8fe 100644
--- a/core/net/packetbuf.h
+++ b/core/net/packetbuf.h
@@ -434,7 +434,7 @@ void              packetbuf_attr_copyfrom(struct packetbuf_attr *attrs,
 
 #define PACKETBUF_ATTR_BIT  1
 #define PACKETBUF_ATTR_BYTE 8
-#define PACKETBUF_ADDRSIZE (sizeof(linkaddr_t) * PACKETBUF_ATTR_BYTE)
+#define PACKETBUF_ADDRSIZE (LINKADDR_SIZE * PACKETBUF_ATTR_BYTE)
 
 struct packetbuf_attrlist {
   uint8_t type;