diff --git a/ChangeLog b/ChangeLog
index 92e80305b..bd673b7e2 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,12 @@
+2000-01-15  OKUJI Yoshinori  <okuji@gnu.org>
+
+	* stage2/builtins.c (chainloader_func): If --force is specified
+	in ARG, don't check for the signature.
+	* docs/tutorial.texi (Chain-loading): Added a caution about some
+	defective boot loaders and --force.
+	* docs/user-ref.texi (Command-line-specific commands): Added a
+	description about --force.
+	
 2000-01-11  OKUJI Yoshinori  <okuji@gnu.org>
 
 	* docs/prog-ref.texi (LBA mode disk I/O): Added a footnote about
diff --git a/NEWS b/NEWS
index c8c9580ec..fc728c53f 100644
--- a/NEWS
+++ b/NEWS
@@ -27,6 +27,9 @@ New in 0.5.94:
   filename from "/boot/grub/menu.lst" even if a Stage 1.5 is used.
 * New program, ``grub-install''.
 * The command "blocklist" prints the blocklist notation of a file.
+* The command "chainloader" now accepts an option "--force", which is
+  required if you want to chain-load a boot loader defective in the
+  signature, such as SCO Unixware 7.1.
 
 New in 0.5.93 - 1999-10-30:
 * ELF format of FreeBSD kernel is supported.
diff --git a/docs/tutorial.texi b/docs/tutorial.texi
index 1079f23c8..4f7cbd45f 100644
--- a/docs/tutorial.texi
+++ b/docs/tutorial.texi
@@ -367,6 +367,12 @@ grub> chainloader +1
 Do not care about what @samp{+1} is. We describe it later in
 @ref{Filesystem}. If this succeeds, run the command @command{boot}.
 
+@strong{Caution:} Some boot loaders (such as the one in SCO Unixware
+7.1) are defective in the signature, so you will have to specify the
+option @option{--force} to @command{chainloader} for them. The option
+might seem to solve your problem, but we strongly recommend reporting
+the bug to the maintainer.
+
 However, some tricks will be necessary if you have installed DOS or
 Windows on a non-first hard disk, because they cannot boot any disks
 except for the first one. The solution is to use the command
diff --git a/docs/user-ref.texi b/docs/user-ref.texi
index 0039bcd5f..2713c333e 100644
--- a/docs/user-ref.texi
+++ b/docs/user-ref.texi
@@ -758,10 +758,13 @@ grub> cat /etc/fstab
 @end example
 @end deffn
 
-@deffn Command chainloader file
+@deffn Command chainloader [@option{--force}] file
 Load @var{file} as a chain-loader. Like any other file loaded by the
 filesystem code, it can use the blocklist notation to grab the first
-sector of the current partition with @samp{+1}.
+sector of the current partition with @samp{+1}. If you specify the
+option @option{--force}, then load @var{file} forcibly, whether it has a
+correct signature or not. This is required when you want to load a
+defective boot loader, such as SCO Unixware 7.1.
 @end deffn
 
 @deffn Command configfile @var{file}
diff --git a/stage2/builtins.c b/stage2/builtins.c
index 8bf7a453c..e419e7a63 100644
--- a/stage2/builtins.c
+++ b/stage2/builtins.c
@@ -268,17 +268,35 @@ static struct builtin builtin_cat =
 static int
 chainloader_func (char *arg, int flags)
 {
-  if (! grub_open (arg))
+  int force = 0;
+  char *file = arg;
+
+  /* If the option `--force' is specified?  */
+  if (substring ("--force", arg) <= 0)
+    {
+      force = 1;
+      file = skip_to (0, arg);
+    }
+
+  /* Open the file.  */
+  if (! grub_open (file))
     {
       kernel_type = KERNEL_TYPE_NONE;
       return 1;
     }
-      
-  if (grub_read ((char *) BOOTSEC_LOCATION, SECTOR_SIZE) == SECTOR_SIZE
+
+  /* Read the first block.  */
+  if (grub_read ((char *) BOOTSEC_LOCATION, SECTOR_SIZE) != SECTOR_SIZE)
+    {
+      grub_close ();
+      kernel_type = KERNEL_TYPE_NONE;
+      return 1;
+    }
+
+  /* If not loading it forcibly, check for the signature.  */
+  if (! force
       && (*((unsigned short *) (BOOTSEC_LOCATION + BOOTSEC_SIG_OFFSET))
-	  == BOOTSEC_SIGNATURE))
-    kernel_type = KERNEL_TYPE_CHAINLOADER;
-  else if (! errnum)
+	  != BOOTSEC_SIGNATURE))
     {
       grub_close ();
       errnum = ERR_EXEC_FORMAT;
@@ -287,6 +305,7 @@ chainloader_func (char *arg, int flags)
     }
 
   grub_close ();
+  kernel_type = KERNEL_TYPE_CHAINLOADER;
   return 0;
 }
 
@@ -295,8 +314,9 @@ static struct builtin builtin_chainloader =
   "chainloader",
   chainloader_func,
   BUILTIN_CMDLINE,
-  "chainloader FILE",
-  "Load the chain-loader FILE."
+  "chainloader [--force] FILE",
+  "Load the chain-loader FILE. If --force is specified, then load it"
+  " forcibly, whether the boot loader signature is present or not."
 };