diff --git a/src/include/lwip/opt.h b/src/include/lwip/opt.h
index 2ae6d67c..c361dcc0 100644
--- a/src/include/lwip/opt.h
+++ b/src/include/lwip/opt.h
@@ -1443,7 +1443,7 @@
  * for an additional encapsulation header before ethernet headers (e.g. 802.11)
  */
 #if !defined PBUF_LINK_ENCAPSULATION_HLEN || defined __DOXYGEN__
-#define PBUF_LINK_ENCAPSULATION_HLEN    0u
+#define PBUF_LINK_ENCAPSULATION_HLEN    0
 #endif
 
 /**