=== modified file 'commands/i386/cmostest.c'
--- commands/i386/cmostest.c	2010-05-22 18:28:09 +0000
+++ commands/i386/cmostest.c	2010-06-28 08:24:28 +0000
@@ -22,20 +22,32 @@
 #include <grub/cmos.h>
 
 static grub_err_t
-grub_cmd_cmostest (struct grub_command *cmd __attribute__ ((unused)),
-		   int argc, char *argv[])
+parse_args (int argc, char *argv[], int *byte, int *bit)
 {
-  int byte, bit;
   char *rest;
 
   if (argc != 1)
     return grub_error (GRUB_ERR_BAD_ARGUMENT, "Address required.");
 
-  byte = grub_strtoul (argv[0], &rest, 0);
+  *byte = grub_strtoul (argv[0], &rest, 0);
   if (*rest != ':')
     return grub_error (GRUB_ERR_BAD_ARGUMENT, "Address required.");
 
-  bit = grub_strtoul (rest + 1, 0, 0);
+  *bit = grub_strtoul (rest + 1, 0, 0);
+
+  return GRUB_ERR_NONE;
+}
+
+static grub_err_t
+grub_cmd_cmostest (struct grub_command *cmd __attribute__ ((unused)),
+		   int argc, char *argv[])
+{
+  int byte, bit;
+  grub_err_t err;
+
+  err = parse_args (argc, argv, &byte, &bit);
+  if (err)
+    return err;
 
   if (grub_cmos_read (byte) & (1 << bit))
     return GRUB_ERR_NONE;
@@ -43,7 +55,22 @@
   return grub_error (GRUB_ERR_TEST_FAILURE, "false");
 }
 
-static grub_command_t cmd;
+static grub_err_t
+grub_cmd_cmosclean (struct grub_command *cmd __attribute__ ((unused)),
+		    int argc, char *argv[])
+{
+  int byte, bit;
+  grub_err_t err;
+
+  err = parse_args (argc, argv, &byte, &bit);
+  if (err)
+    return err;
+
+  grub_cmos_write (byte, grub_cmos_read (byte) & (~(1 << bit)));
+  return GRUB_ERR_NONE;
+}
+
+static grub_command_t cmd, cmd_clean;
 
 
 GRUB_MOD_INIT(cmostest)
@@ -51,9 +78,13 @@
   cmd = grub_register_command ("cmostest", grub_cmd_cmostest,
 			       "cmostest BYTE:BIT",
 			       "Test bit at BYTE:BIT in CMOS.");
+  cmd_clean = grub_register_command ("cmosclean", grub_cmd_cmosclean,
+				     "cmosclean BYTE:BIT",
+				     "Clean bit at BYTE:BIT in CMOS.");
 }
 
 GRUB_MOD_FINI(cmostest)
 {
   grub_unregister_command (cmd);
+  grub_unregister_command (cmd_clean);
 }

=== modified file 'util/grub-mkconfig.in'
--- util/grub-mkconfig.in	2010-06-28 00:39:49 +0000
+++ util/grub-mkconfig.in	2010-06-28 08:26:35 +0000
@@ -254,6 +254,7 @@
   GRUB_HIDDEN_TIMEOUT_BUTTON \
   GRUB_TIMEOUT_BUTTON \
   GRUB_BUTTON_CMOS_ADDRESS \
+  GRUB_BUTTON_CMOS_CLEAN \
   GRUB_DISTRIBUTOR \
   GRUB_CMDLINE_LINUX \
   GRUB_CMDLINE_LINUX_DEFAULT \

=== modified file 'util/grub.d/00_header.in'
--- util/grub.d/00_header.in	2010-06-17 15:01:17 +0000
+++ util/grub.d/00_header.in	2010-06-28 08:25:59 +0000
@@ -253,6 +253,12 @@
 make_timeout "${GRUB_HIDDEN_TIMEOUT}" "${GRUB_TIMEOUT}"
 fi
 
+if [ "x$GRUB_BUTTON_CMOS_ADDRESS" != "x" ] && [ "x$GRUB_BUTTON_CMOS_CLEAN" != "xyes" ]; then
+    cat <<EOF
+cmosclean $GRUB_BUTTON_CMOS_ADDRESS
+EOF
+fi
+
 # Play an initial tune
 if [ "x${GRUB_INIT_TUNE}" != "x" ] ; then
   cat << EOF