Saturday, April 17, 2010

How to Recover Gnu/Linux Grub After Windows Installation

How to Recover Gnu/Linux Grub After Windows Installation


Today i destroyed my Grub2 via installing windows on my notebook which .
Here is the step by step guide to recover Grand Unified BootLoader(Grub) :

You will need a LIVE cd if you are going to recover an Ubuntu Box.Download Ubuntu Jaunty, Karmic whatever you want.Open the system with Live CD (I assume you are using Ubuntu Live CD).

$sudo fdisk -l

This will show your partition table.Here is my table to understand it better :

/dev/sda1 29 8369 66999082+ 83 Linux
/dev/sda2 * 8370 13995 45190845 7 HPFS/NTFS
/dev/sda3 13996 14593 4803435 5 Extended
/dev/sda5 13996 14593 4803403+ 82 Linux swap / Solaris

Now i will mount Linux (sda1 here), i have no external boot partition as you can see.(IF YOU HAVE external one, do not forget to mount it! )

$sudo mount /dev/sda1 /mnt
$sudo mount --bind /dev /mnt/dev
$sudo mount --bind /proc /mnt/proc

The following command is optional (it copies resolv.conf)

$sudo cp /etc/resolv.conf /mnt/etc/resolv.conf

Now chroot into the enviroment we made :

sudo chroot /mnt

After chrooting, you do not need to add sudo before your commands because from now, you will run commands as root.

You may want to edit /etc/default/grub file to fit your system (timeout options etc)

#nano -w /etc/default/grub

Play with the options if you want.(But do not forget to give grub-update command if you saved it ;) )

Now install/recover Grub2 via :

#grub-install /dev/sda

command.However you may get errors with that code like me.If so please use this command :

#grub-install --recheck /dev/sda

Now you can exit the chroot, umount the system and reboot your box :

#exit
$sudo umount /mnt/dev
$sudo umount /mnt/proc
$sudo umount /mnt
$sudo reboot

I hope the Grub will be acitve and working fine

Thank you so much for visiting my blog !!

2 comments:

Dilip Reddy said...

Thanks for the post.
been searching for a good one for a while..

gyani said...

Thank you