2009-12-25 Vladimir Serbinenko <phcoder@gmail.com>

* kern/i386/pc/startup.S (grub_biosdisk_get_diskinfo_int13_extensions):
	Ignore return status if CF is cleared.
	(grub_biosdisk_get_diskinfo_standard): Likewise.

kern/i386/pc/startup.S

@@ -764,6 +764,11 @@ FUNCTION(grub_biosdisk_get_diskinfo_int13_extensions)
 	movw	%cx, %ax
 	movw	%bx, %ds
 	int	$0x13		/* do the operation */
+	jc      noclean
+	/* Clean return value if carry isn't set to workaround
+	some buggy BIOSes.  */
+	xor     %ax, %ax
+noclean:
 	movb	%ah, %bl	/* save return value in %bl */
 	/* back to protected mode */
 	DATA32	call	real_to_prot
@@ -807,6 +812,11 @@ FUNCTION(grub_biosdisk_get_diskinfo_standard)
 	.code16
 	movb	$0x8, %ah
 	int	$0x13		/* do the operation */
+	jc      noclean2
+	/* Clean return value if carry isn't set to workaround
+	some buggy BIOSes.  */
+	xor     %ax, %ax
+noclean2:
 	/* check if successful */
 	testb	%ah, %ah
 	jnz	1f