Fixing a Grub Error 15 from a Partition Resize

Wow, that was close! I decided to delete an old fat32 partition that I used to share data between linux (first Fedora, now Ubuntu) and Windows on my dual boot PC. Since Ubuntu supports NTFS partitions, I hardly ever used it. I used Partition Manager Professional in Windows to delete the partition. No worries. However, I also decided to resize my /boot partition under Ubuntu. When I recently upgraded to Ubuntu 8.04, the process was stalled several times because I didn't have enough space on the /boot partition (initially 100Mb). This was very annoying because I had to move some files from /boot and restart the entire Ubuntu upgrade (several minutes wasted each time). So I used Partition Manager to also increase the /boot partition to 200MB. No worries. Or so it seemed until I reboot my PC. After the BIOS startup, Grub reported an Error 15 and halted. No Grub menu. No option to boot into Windows or Ubuntu! Luckily I've got a System Rescue CD which gives a basic Linux OS when booting from the CD. After reading a few forums online (via my text-based web server) I found my problem and solution. The problem was GRUB in the /boot partition was on installed (hd0,5), but after making changes to my partitions it was now on (hd0,6). To fix this I had to modify my /boot/grub/menu.lst file and re-install Grub as follows: Once the SystemRescue OS had booted, mount the drive containing the /boot partition, e.g.:

mkdir /mnt/tmp1
mount -t ext3 /dev/sda6 /mnt/tmp1

Edit the Grub menu file and change references of (hd0,5) to (hd0,6). Then start Grub and execute:

grub
root (hd0,6)
setup (hd0)

This loads the Grub files into the Master Boot Record (MBR) to point to the /boot partition. A reboot and things were back to normal (oh, except for a few filesystem errors which were soon fixed).

Created on Thu, 22 May 2008, 6:58pm

Last changed on Thu, 22 May 2008, 6:59pm