diff --git a/ChangeLog b/ChangeLog
index 5450e7b57..c7075d681 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,41 @@
+2008-02-03  Yoshinori K. Okuji  <okuji@enbug.org>
+
+	Add support for having a grub directory in a different drive. This
+	is still only the data handling part.
+	
+	* kern/i386/pc/startup.S (multiboot_trampoline): Set %dh to 0xFF.
+	(codestart): Save %dh in GRUB_ROOT_DRIVE.
+	(grub_root_drive): New variable.
+
+	* kern/i386/pc/init.c (make_install_device): Use GRUB_ROOT_DRIVE
+	instead of GRUB_BOOT_DRIVE to construct a device name. Set
+	GRUB_ROOT_DRIVE to GRUB_BOOT_DRIVE if it is 0xFF, otherwise use it
+	as it was.
+
+	* include/grub/i386/pc/kernel.h (grub_root_drive): New prototype.
+
+	* include/grub/i386/pc/boot.h (GRUB_BOOT_MACHINE_ROOT_DRIVE): New
+	macro.
+	(GRUB_BOOT_MACHINE_DRIVE_CHECK): Set to 0x4f.
+
+	* boot/i386/pc/pxeboot.S (_start): Set %dh to 0xFF. For now, this
+	is bogus, because PXE booting does not specify any drive
+	correctly.
+
+	* boot/i386/pc/lnxboot.S (reg_edx): Set the second byte to 0xFF. I
+	am not sure if this is really correct.
+
+	* boot/i386/pc/cdboot.S: Set %dh to 0xFF, because the root drive
+	is always identical to the boot drive when booting from a CD.
+
+	* boot/i386/pc/boot.S (MOV_MEM_TO_AL): Removed. Not needed any
+	longer.
+	(root_drive): New variable.
+	(real_start): Unconditionally set %dh to ROOT_DRIVE.
+	(setup_sectors): Push %dx right after popping it, because %dh will
+	be modified later.
+	(copy_buffer): Restore %dx.
+
 2008-02-03  Robert Millan  <rmh@aybabtu.com>
 
 	* util/i386/pc/grub-mkrescue.in: Rewrite most of image generation to
diff --git a/boot/i386/pc/boot.S b/boot/i386/pc/boot.S
index 187b7d2d4..64d40c8fb 100644
--- a/boot/i386/pc/boot.S
+++ b/boot/i386/pc/boot.S
@@ -32,9 +32,6 @@
 	/* Print message string */
 #define MSG(x)	movw $ABS(x), %si; call message
 
-	/* XXX:	binutils-2.9.1.0.x doesn't produce a short opcode for this. */
-#define	MOV_MEM_TO_AL(x)	.byte 0xa0;  .word x
-	
 	.file	"boot.S"
 
 	.text
@@ -99,6 +96,8 @@ kernel_sector:
 boot_drive:	
 	.byte 0xff	/* the disk to load kernel from */
 			/* 0xff means use the boot drive */
+root_drive:
+        .byte 0xff
 
 after_BPB:
 
@@ -141,7 +140,9 @@ real_start:
 	/*
 	 *  Check if we have a forced disk reference here
 	 */
-	MOV_MEM_TO_AL(ABS(boot_drive))	/* movb	ABS(boot_drive), %al */
+        /* assign root_drive at the same time */
+        movw    ABS(boot_drive), %ax
+        movb    %ah, %dh
 	cmpb	$0xff, %al
 	je	1f
 	movb	%al, %dl
@@ -303,6 +304,7 @@ setup_sectors:
 
 	/* restore %dl */
 	popw	%dx
+        pushw   %dx
 
 	/* head start */
 	movb	%al, %dh
@@ -353,6 +355,7 @@ copy_buffer:
 
 	popw	%ds
 	popa
+        popw    %dx
 
 	/* boot kernel */
 	jmp	*(kernel_address)
diff --git a/boot/i386/pc/cdboot.S b/boot/i386/pc/cdboot.S
index 61ef84ee9..1709b8c89 100644
--- a/boot/i386/pc/cdboot.S
+++ b/boot/i386/pc/cdboot.S
@@ -78,6 +78,9 @@ bi_reserved:
 
 	call	read_cdrom
 
+        /* Root drive will default to boot drive */
+        movb    $0xFF, %dh
+        
 	ljmp	$(DATA_ADDR >> 4), $0
 
 /*
diff --git a/boot/i386/pc/lnxboot.S b/boot/i386/pc/lnxboot.S
index 6a4de8dd5..2a913ba9c 100644
--- a/boot/i386/pc/lnxboot.S
+++ b/boot/i386/pc/lnxboot.S
@@ -115,7 +115,7 @@ gdt_dst2:
 	.long	0, 0, 0, 0		/* More space for the BIOS.  */
 
 reg_edx:
-	.byte	0x80,0,0xFF,0xFF
+	.byte	0x80, 0xFF, 0xFF, 0xFF
 
 data_leng:
 	.long	0
diff --git a/boot/i386/pc/pxeboot.S b/boot/i386/pc/pxeboot.S
index 8c547733a..7f2a14396 100644
--- a/boot/i386/pc/pxeboot.S
+++ b/boot/i386/pc/pxeboot.S
@@ -1,6 +1,6 @@
 /*
  *  GRUB  --  GRand Unified Bootloader
- *  Copyright (C) 2000,2005,2007   Free Software Foundation, Inc.
+ *  Copyright (C) 2000,2005,2007,2008   Free Software Foundation, Inc.
  *
  *  GRUB is free software: you can redistribute it and/or modify
  *  it under the terms of the GNU General Public License as published by
@@ -25,6 +25,9 @@
 	/* Let's go */
 .globl _start; _start:
 
+        /* Root drive will default to boot drive */
+        movb    $0xFF, %dh
+        
 	/* Jump to the real world */
 	ljmp	$0, $0x8200
 
diff --git a/include/grub/i386/pc/boot.h b/include/grub/i386/pc/boot.h
index fcc961b1a..386221414 100644
--- a/include/grub/i386/pc/boot.h
+++ b/include/grub/i386/pc/boot.h
@@ -1,6 +1,6 @@
 /*
  *  GRUB  --  GRand Unified Bootloader
- *  Copyright (C) 1999,2000,2002,2005,2006,2007   Free Software Foundation, Inc.
+ *  Copyright (C) 1999,2000,2002,2005,2006,2007,2008   Free Software Foundation, Inc.
  *
  *  GRUB is free software: you can redistribute it and/or modify
  *  it under the terms of the GNU General Public License as published by
@@ -34,6 +34,9 @@
 /* The offset of BOOT_DRIVE.  */
 #define GRUB_BOOT_MACHINE_BOOT_DRIVE	0x4c
 
+/* The offset of ROOT_DRIVE.  */
+#define GRUB_BOOT_MACHINE_ROOT_DRIVE	0x4d
+
 /* The offset of KERNEL_ADDRESS.  */
 #define GRUB_BOOT_MACHINE_KERNEL_ADDRESS	0x40
 
@@ -44,7 +47,7 @@
 #define GRUB_BOOT_MACHINE_KERNEL_SEGMENT	0x42
 
 /* The offset of BOOT_DRIVE_CHECK.  */
-#define GRUB_BOOT_MACHINE_DRIVE_CHECK	0x4e
+#define GRUB_BOOT_MACHINE_DRIVE_CHECK	0x4f
 
 /* The offset of a magic number used by Windows NT.  */
 #define GRUB_BOOT_MACHINE_WINDOWS_NT_MAGIC	0x1b8
diff --git a/include/grub/i386/pc/kernel.h b/include/grub/i386/pc/kernel.h
index ca16df788..848dad10d 100644
--- a/include/grub/i386/pc/kernel.h
+++ b/include/grub/i386/pc/kernel.h
@@ -1,6 +1,6 @@
 /*
  *  GRUB  --  GRand Unified Bootloader
- *  Copyright (C) 2002,2003,2007  Free Software Foundation, Inc.
+ *  Copyright (C) 2002,2003,2007,2008  Free Software Foundation, Inc.
  *
  *  GRUB is free software: you can redistribute it and/or modify
  *  it under the terms of the GNU General Public License as published by
@@ -73,6 +73,9 @@ extern char grub_prefix[];
 /* The boot BIOS drive number.  */
 extern grub_int32_t grub_boot_drive;
 
+/* The root BIOS drive number.  */
+extern grub_int32_t grub_root_drive;
+
 /* The end address of the kernel.  */
 extern grub_addr_t grub_end_addr;
 
diff --git a/kern/i386/pc/init.c b/kern/i386/pc/init.c
index 908e2d791..72374929c 100644
--- a/kern/i386/pc/init.c
+++ b/kern/i386/pc/init.c
@@ -72,13 +72,18 @@ make_install_device (void)
     }
   else if (grub_install_dos_part != -2)
     {
-      if (grub_boot_drive >= GRUB_BIOSDISK_MACHINE_CDROM_START)
+      /* If the root drive is not set explicitly, assume that it is identical
+         to the boot drive.  */
+      if (grub_root_drive == 0xFF)
+        grub_root_drive = grub_boot_drive;
+      
+      if (grub_root_drive >= GRUB_BIOSDISK_MACHINE_CDROM_START)
         grub_sprintf (dev, "(cd%u",
-		      grub_boot_drive - GRUB_BIOSDISK_MACHINE_CDROM_START);
+		      grub_root_drive - GRUB_BIOSDISK_MACHINE_CDROM_START);
       else
         grub_sprintf (dev, "(%cd%u",
-		      (grub_boot_drive & 0x80) ? 'h' : 'f',
-		      grub_boot_drive & 0x7f);
+		      (grub_root_drive & 0x80) ? 'h' : 'f',
+		      grub_root_drive & 0x7f);
       
       if (grub_install_dos_part >= 0)
 	grub_sprintf (dev + grub_strlen (dev), ",%u", grub_install_dos_part + 1);
diff --git a/kern/i386/pc/startup.S b/kern/i386/pc/startup.S
index 0bfe2b37d..0a38b994c 100644
--- a/kern/i386/pc/startup.S
+++ b/kern/i386/pc/startup.S
@@ -1,6 +1,6 @@
 /*
  *  GRUB  --  GRand Unified Bootloader
- *  Copyright (C) 1999,2000,2001,2002,2003,2005,2006,2007 Free Software Foundation, Inc.
+ *  Copyright (C) 1999,2000,2001,2002,2003,2005,2006,2007,2008 Free Software Foundation, Inc.
  *
  *  GRUB is free software: you can redistribute it and/or modify
  *  it under the terms of the GNU General Public License as published by
@@ -162,6 +162,7 @@ multiboot_trampoline:
 	movl	%ebx, EXT_C(grub_install_bsd_part)
 2:
 	shrl	$24, %edx
+        movb    $0xFF, %dh
 	/* enter the usual booting */
 	call	prot_to_real
 	.code16
@@ -182,8 +183,9 @@ codestart:
 
 	sti		/* we're safe again */
 
-	/* save boot drive reference */
+	/* save boot and root drive references */
 	ADDR32	movb	%dl, EXT_C(grub_boot_drive)
+	ADDR32	movb	%dh, EXT_C(grub_root_drive)
 
 	/* reset disk system (%ah = 0) */
 	int	$0x13
@@ -255,6 +257,9 @@ codestart:
 VARIABLE(grub_boot_drive)
 	.long	0
 
+VARIABLE(grub_root_drive)
+	.long	0
+
 VARIABLE(grub_start_addr)
 	.long	START_SYMBOL