diff -Naur orig/contrib/ports/unix/proj/minimal/echo.c patched/contrib/ports/unix/proj/minimal/echo.c
--- orig/contrib/ports/unix/proj/minimal/echo.c	2006-09-27 13:00:42.000000000 +0200
+++ patched/contrib/ports/unix/proj/minimal/echo.c	2009-04-18 00:10:04.000000000 +0200
@@ -189,7 +189,7 @@
 
       /* chain pbufs to the end of what we recv'ed previously  */
       ptr = es->p;
-      pbuf_chain(ptr,p);
+      pbuf_cat(ptr,p);
     }
     ret_err = ERR_OK;
   }
@@ -311,12 +311,9 @@
        pbuf_ref(es->p);
      }
      /* chop first pbuf from chain */
-      do
-      {
-        /* try hard to free pbuf */
-        freed = pbuf_free(ptr);
-      }
-      while(freed == 0);
+     /* free pbuf */
+     freed = pbuf_free(ptr);
+     LWIP_ASSERT("freed != 0", freed != 0);
      /* we can read more data now */
      tcp_recved(tpcb, plen);
    }