diff --git a/CHANGELOG b/CHANGELOG
index cb0b4ccb..1781b64a 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -599,6 +599,7 @@ HISTORY
   2008-03-04 Jonathan Larmour
   * mem.c, stats.c, mem.h: apply patch #6414 to avoid compiler errors
   and/or warnings on some systems where mem_size_t and size_t differ.
+  * pbuf.c, ppp.c: Fix warnings on some systems with mem_malloc.
 
   2008-03-04 Kieran Mansley (contributions by others) 
   * Numerous small compiler error/warning fixes from contributions to
diff --git a/src/core/pbuf.c b/src/core/pbuf.c
index c176adbe..8d935b02 100644
--- a/src/core/pbuf.c
+++ b/src/core/pbuf.c
@@ -207,7 +207,7 @@ pbuf_alloc(pbuf_layer layer, u16_t length, pbuf_type type)
     break;
   case PBUF_RAM:
     /* If pbuf is to be allocated in RAM, allocate memory for it. */
-    p = mem_malloc(LWIP_MEM_ALIGN_SIZE(SIZEOF_STRUCT_PBUF + offset) + LWIP_MEM_ALIGN_SIZE(length));
+    p = (struct pbuf*)mem_malloc(LWIP_MEM_ALIGN_SIZE(SIZEOF_STRUCT_PBUF + offset) + LWIP_MEM_ALIGN_SIZE(length));
     if (p == NULL) {
       return NULL;
     }
diff --git a/src/netif/ppp/ppp.c b/src/netif/ppp/ppp.c
index 9b45f543..b84ccbfa 100644
--- a/src/netif/ppp/ppp.c
+++ b/src/netif/ppp/ppp.c
@@ -400,7 +400,7 @@ pppInit(void)
 
     subnetMask = htonl(0xffffff00);
 
-    outpacket_buf[i] = mem_malloc(PPP_MRU+PPP_HDRLEN);
+    outpacket_buf[i] = (u_char *)mem_malloc(PPP_MRU+PPP_HDRLEN);
     if(!outpacket_buf[i]) {
       return ERR_MEM;
     }