diff --git a/src/core/pbuf.c b/src/core/pbuf.c
index 300c0da1..1d64a7d5 100644
--- a/src/core/pbuf.c
+++ b/src/core/pbuf.c
@@ -543,9 +543,9 @@ pbuf_header_impl(struct pbuf *p, s16_t header_size_increment, u8_t force)
     p->payload = (u8_t *)p->payload - header_size_increment;
     /* boundary check fails? */
     if ((u8_t *)p->payload < (u8_t *)p + SIZEOF_STRUCT_PBUF) {
-      LWIP_DEBUGF( PBUF_DEBUG | LWIP_DBG_LEVEL_SERIOUS,
+      LWIP_DEBUGF( PBUF_DEBUG | LWIP_DBG_TRACE,
         ("pbuf_header: failed as %p < %p (not enough space for new header size)\n",
-        (void *)p->payload, (void *)(p + 1)));
+        (void *)p->payload, (void *)((u8_t *)p + SIZEOF_STRUCT_PBUF)));
       /* restore old payload pointer */
       p->payload = payload;
       /* bail out unsuccessfully */