diff --git a/src/include/lwip/raw.h b/src/include/lwip/raw.h
index 58b9a867..46007fe7 100644
--- a/src/include/lwip/raw.h
+++ b/src/include/lwip/raw.h
@@ -59,7 +59,7 @@ err_t            raw_bind       (struct raw_pcb *pcb, struct ip_addr *ipaddr);
 err_t            raw_connect    (struct raw_pcb *pcb, struct ip_addr *ipaddr);
 
 void             raw_recv       (struct raw_pcb *pcb,
-                                 int (* recv)(void *arg, struct raw_pcb *pcb,
+                                 u8_t (* recv)(void *arg, struct raw_pcb *pcb,
                                               struct pbuf *p,
                                               struct ip_addr *addr),
                                  void *recv_arg);