diff --git a/ChangeLog b/ChangeLog
index 5855a3e6f..666b14e91 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+2002-05-20  Yoshinori K. Okuji  <okuji@enbug.org>
+
+	* lib/device.c (read_device_map): Show an error message and exit
+	abnormally, if MAP[DRIVE] has already been filled.
+	* util/grub-install.in: If there is any dulicated entry, print
+	an error message and exit abnormally.
+	
 2002-05-20  Yoshinori K. Okuji  <okuji@enbug.org>
 
 	* lib/device.c: Don't include linux/hdreg.h, linux/major.h,
diff --git a/lib/device.c b/lib/device.c
index f130cad8f..72903c9eb 100644
--- a/lib/device.c
+++ b/lib/device.c
@@ -454,6 +454,13 @@ read_device_map (FILE *fp, char **map, const char *map_file)
       while (*eptr && ! isspace (*eptr))
 	eptr++;
       *eptr = 0;
+
+      /* Multiple entries for a given drive is not allowed.  */
+      if (map[drive])
+	{
+	  show_error (line_number, "Duplicated entry found");
+	  return 0;
+	}
       
       map[drive] = strdup (ptr);
       assert (map[drive]);
diff --git a/util/grub-install.in b/util/grub-install.in
index 21df9eb51..e024cd376 100644
--- a/util/grub-install.in
+++ b/util/grub-install.in
@@ -323,6 +323,14 @@ EOF
     rm -f $log_file
 fi
 
+# Make sure that there is no duplicated entry.
+tmp=`sed -n '/^([fh]d[0-9]*)/s/\(^(.*)\).*/\1/p' $device_map \
+    | sort | uniq -d | sed -n 1p`
+if test -n "$tmp"; then
+    echo "The drive $tmp is defined multiple times in the device map $device_map" 1>&2
+    exit 1
+fi
+
 # Check for INSTALL_DEVICE.
 case "$install_device" in
 /dev/*)