Reactivating Linux Loaders (GRUB, LILO)

Do you want to know how to reactivate Linux loaders GRUB and LILO? Then please read on.

GRUB

1. Boot from Linux installation CD and enter rescue mode;
2. Mount all partitions and change root from the temporary root to the root partition of the installed system:
   • #mkdir /mnt/tmp
   • #mount /dev/sdXY /mnt/tmp (/dev/sdXY is the root partition)
   • #chroot /mnt/tmp
3. Generate /etc/mtab:
   • #grep -v rootfs /proc/mounts > /etc/mtab
4. Check if the GRUB configuration file is correct:
   GRUB stores its configuration in either /boot/grub/grub.conf or /boot/grub/menu.lst depending on the distribution you are using.
5. Reactivate GRUB automatically:
   Run the following command:
   • #grub-install /dev/
     [device name]

   where /dev/[device name] is the name of disk/partition where you are going to install GRUB.

   For example, the following command will install GRUB to the MBR of disk /dev/sda:

    

   • #grub-install /dev/sda
6. Reactivate GRUB manually in case Step 5 fails:
   • #/sbin/grub

   You will receive a prompt:

   grub>

   Please issue the commands (4 is the root partition in this example):

   grub>root (hd0,4)
   grub> setup (hd0)

   You will see the output:

   Checking if “/boot/grub/stage1” exists… yes
   Checking if “/boot/grub/stage2” exists… yes
   Checking if “/boot/grub/reiserfs_stage1_5” exists… yes
   Running “embed /boot/grub/reiserfs_stage1_5 (hd0)”… 18 sectors are embedded
   .
   succeeded
   Running “install /boot/grub/stage1 (hd0) (hd0)1+18 p (hd0,4)/boot/grub/stage2

   
   

   /boot/grub/grub.conf”… succeeded
   Done.
   grub>
7. Reboot.

LILO

1. Boot from Linux installation CD and enter rescue mode;
2. Mount all partitions and change root from the temporary root to the root partition of the installed system:
   • #mkdir /mnt/tmp
   • #mount /dev/sdXY /mnt/tmp (/dev/sdXY is the root partition)
   • #chroot /mnt/tmp
3. Run the following command to reactivate LILO:
   • #/sbin/lilo