diff --git a/CHANGELOG b/CHANGELOG
index cbf0edf0..b457e9b6 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -66,7 +66,11 @@ HISTORY
   * api_lib.c: Use memcpy in netbuf_copy_partial.
 
   ++ Bug fixes:
-  
+
+  2007-03-20 Kieran Mansley
+  * udp.c: Only try and use pbuf_header() to make space for headers if
+    not a ROM or REF pbuf.
+
   2007-03-19 Frédéric Bernon
   * api_msg.h, api_msg.c, tcpip.h, tcpip.c: Add return types to tcpip_apimsg()
     and api_msg_post().
diff --git a/src/core/udp.c b/src/core/udp.c
index 6f3de7be..51daba7c 100644
--- a/src/core/udp.c
+++ b/src/core/udp.c
@@ -319,7 +319,7 @@ udp_send(struct udp_pcb *pcb, struct pbuf *p)
   }
 
   /* not enough space to add an UDP header to first pbuf in given p chain? */
-  if (pbuf_header(p, UDP_HLEN)) {
+  if (p->flags == PBUF_FLAG_ROM || p->flags == PBUF_FLAG_REF || pbuf_header(p, UDP_HLEN)) {
     /* allocate header in a seperate new pbuf */
     q = pbuf_alloc(PBUF_IP, UDP_HLEN, PBUF_RAM);
     /* new header pbuf could not be allocated? */