[The Computer Kid] How To Fix Grub From a Live CD / USB

[Conrad Sykes]

Grub can break for a variety of reasons and since it typically prevents you from starting your system, fixing it requires the use of Live CD.  Once you have a live Linux CD or USB follow the instructions below to reinstall Grub on your system.

Note: Before starting make sure that the live CD/USB you are using is the same sort of architecture as the system you are trying to rescue. In other words if the system is 32 bit then use a 32 bit live cd or if it's 64 bit then use a 64 bit live cd or else when you try to chroot you will get a “Exec format error”.

Sudo mount -t ext4 /dev/sdaX /mnt

You can replace "ext4" with the appropriate file system type

sudo mount -t proc none /mnt/proc
sudo mount -o bind /dev /mnt/dev

Allows the chrooted system to find your system partitions

sudo chroot /mnt

chroots into the system we have mounted and bound

sudo grub-install /dev/sda

installs grub to the hard drive

Now restart your computer. Remove the live CD/USB, and grub should be fixed.

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Posted By Conrad Sykes to The Computer Kid at 6/19/2013 03:02:00 PM