Datasheet

“main” (Installation and Administration) — 2004/6/25 — 13:29 — page 226 — #252

8.7 Uninstalling the Linux Boot Loader

There are two ways to uninstall the Linux boot loader:

Restore the backup of the original MBR by means of the YaST boot

loader module. YaST creates this backup automatically.

Install a different boot loader or restore the DOS or Windows MBR.

Caution

Invalid Backups of Boot Sectors

A boot sector backup is no longer valid if the partition in ques-

tion has a new ﬁle system. The partition table of an MBR backup

becomes invalid if the hard disk has been repartitioned since the

backup was created. Obsolete backups are time bombs. It is best

to delete them from /boot/backup.mbr promptly.

Caution

8.7.1 Restoring the MBR (DOS, Win9x, or ME)

It is very simple to restore a DOS or Windows MBR. Just enter the MS-

DOS command (available since DOS version 5.0) fdisk /MBR. These

commands only write the ﬁrst 446 bytes (the boot code) into the MBR and

leave the partition table untouched, unless the MBR as a whole (see Sec-

tion 8.1.1 on page 204) is treated as invalid due to an incorrect magic num-

ber. In this case, the partition table is set to zero. After restoring the MBR,

mark the desired start partition as bootable (using fdisk again). This is re-

quired for the MBR routines of DOS and Windows.

8.7.2 Restoring the MBR of Windows XP

Boot from the Windows XP CD and press









R during the setup to start the

recovery console. Select your Windows XP installation from the list and en-

ter the administrator password. At the input prompt, enter the command

FIXMBR and conﬁrm with y when asked to do so. Then reboot the com-

puter with exit.

226 8.7. Uninstalling the Linux Boot Loader