--- yaboot-1.3.17/second/prom.c.orig	2011-10-18 12:41:46.924310275 +1100
+++ yaboot-1.3.17/second/prom.c	2011-10-18 12:43:17.202121228 +1100
@@ -622,6 +622,11 @@
      void *ret;
 
      ret = call_prom ("claim", 3, 1, virt, size, align);
+
+     /* Pegasos II SmartFirmware returns zero for failure, usefully */
+     if (virt && !ret)
+          ret = (void *)-1;
+
      if (ret == (void *)-1)
           prom_printf("ERROR: claim of 0x%x at 0x%x failed\n", size, (int)virt);
      else