diff --git a/ChangeLog b/ChangeLog
index d7606da2a..31aa19bad 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+2010-12-27  Vladimir Serbinenko  <phcoder@gmail.com>
+
+	* grub-core/loader/xnu.c (grub_cmd_xnu_kext): Abort if no kernel
+	is loaded
+	(grub_cmd_xnu_kextdir): Likewise.
+	(grub_cmd_xnu_splash): Likewise.
+
 2010-12-27  Vladimir Serbinenko  <phcoder@gmail.com>
 
 	Avoid using Reed-Solomon with 0 redundancy.
diff --git a/grub-core/loader/xnu.c b/grub-core/loader/xnu.c
index d0b32dc6f..02151dd9c 100644
--- a/grub-core/loader/xnu.c
+++ b/grub-core/loader/xnu.c
@@ -1198,6 +1198,10 @@ grub_cmd_xnu_kext (grub_command_t cmd __attribute__ ((unused)),
 		   int argc, char *args[])
 {
   grub_file_t binfile = 0;
+
+  if (! grub_xnu_heap_size)
+    return grub_error (GRUB_ERR_BAD_OS, "no xnu kernel loaded");
+
   if (argc == 2)
     {
       /* User explicitly specified plist and binary. */
@@ -1229,6 +1233,9 @@ grub_cmd_xnu_kextdir (grub_command_t cmd __attribute__ ((unused)),
   if (argc != 1 && argc != 2)
     return grub_error (GRUB_ERR_BAD_ARGUMENT, "directory name required");
 
+  if (! grub_xnu_heap_size)
+    return grub_error (GRUB_ERR_BAD_OS, "no xnu kernel loaded");
+
   if (argc == 1)
     return grub_xnu_scan_dir_for_kexts (args[0],
 					"console,root,local-root,network-root",
@@ -1370,6 +1377,9 @@ grub_cmd_xnu_splash (grub_extcmd_context_t ctxt,
   if (argc != 1)
     return grub_error (GRUB_ERR_BAD_ARGUMENT, "file name required");
 
+  if (! grub_xnu_heap_size)
+    return grub_error (GRUB_ERR_BAD_OS, "no xnu kernel loaded");
+
   if (ctxt->state[XNU_SPLASH_CMD_ARGINDEX_MODE].set &&
       grub_strcmp (ctxt->state[XNU_SPLASH_CMD_ARGINDEX_MODE].arg,
 		   "stretch") == 0)