After deleting old Linux partitions in order to free space on hard disk, I got an error from GRUB:

error: no such partition

And then I saw a grub rescue> prompt. After googling around I found that in order to boot normally I have to type the following commands.

set prefix=(hd0,msdos5)/boot/grub
set root=(hd0,msdos5)
insmod /boot/grub/linux.mod
linux /vmlinuz root=/dev/sda5 ro
initrd /initrd.img

Here is the boot info summary report created by Boot-Repair.

However, on each reboot I have to type this again. How can I tell to GRUB once and all what configuration file to use?

  • I have the exact same problem, however when I try to use insmod I'm prompted with error: unknown filesystem.. When I ls I'm presented with (hd0) (hd0,msdos2) (hd0,msdos1). I've tried setting either of these as prefix and then root but whenever I try to insmod I'm prompted with the same error: unknown filesystem.. What can I do?
    – Piper
    May 8, 2013 at 17:02
  • 1
    @PolyShell I think you better ask this as a separate question.
    – jutky
    May 8, 2013 at 19:47

2 Answers 2


Try these commands

sudo update-grub
sudo grub-install /dev/sda

If you want a graphical option, try boot-repair

sudo add-apt-repository ppa:yannubuntu/boot-repair && sudo apt-get update
sudo apt-get install -y boot-repair && boot-repair

enter image description here

  • Thanks a lot. Previously I was running Boot-Repair from a liveCD and it didn't helped, and after I've found what commands to type in grub rescue I haven't tried it once again. Thanks again.
    – jutky
    Dec 26, 2011 at 0:28

Did you run update-grub to update /boot/grub/grub.cfg?

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.