diff --git a/drivers/net/rckemac.c b/drivers/net/rckemac.c
index e13ef5d1..4d6d03e5 100644
--- a/drivers/net/rckemac.c
+++ b/drivers/net/rckemac.c
@@ -354,6 +354,7 @@ static void rckemacif_input(struct netif* netif, struct pbuf* p)
 		}
 		break;
 	default:
+		LWIP_DEBUGF(NETIF_DEBUG, ("rckemacif_input: invalid ethernet header: 0x%x\n", htons(ethhdr->type)));
 		pbuf_free_callback(p);
 		break;
 	}