GRUB 2.0 problems with old grub

[ElevenWarrior]

okay, so here's my problem

I have installed, Ubuntu 10.4, Windows 7, and backtrack 4.
I have to install them in this order (windows, backtrack, then ubuntu) otherwise it woln't work.
well backtrack released a new distro so I have to reinstall it.
if I do, what happens is backtrack 4 grub overwrites the 10.4 grub, but the backtrack grub (1.95 I think) will NOT boot into ubuntu.

So basically, I need to know how to (after reinstalling backtrack 4) to tell the machine to use the ubuntu grub, (2.0) instead of the backtrack grub. (older verison)
Any ideas?

[drs305]

If you want Ubuntu's Grub2 to control things, reinstall Grub2 from the Ubuntu Live CD:


sudo mount /dev/sdXY /mnt
sudo grub-install --root-directory=/mnt /dev/sdX


For example, if your Ubuntu install is on sda5, the commands would be:

sudo mount /dev/sda5 /mnt
sudo grub-install --root-directory=/mnt /dev/sda


This will install Ubuntu's grub on the MBR of the device you designate (example: sda) and write the grub files to the Ubuntu partition (example sda5).

Grub2 should recognize your other OS's. If it doesn't, run "sudo update-grub" after booting into your normal Ubuntu OS.

[ElevenWarrior]

I tried doing those steps you said, but it didn't work.
I installed grub to the right part of the drive, but at next start up, the old grub was still there.
It did, however, say I was installing the GRUB to only that partition and not the MBR, which it said was a bad idea.
still stuck,

[oldfred]

You installed to the partition not the drive. Drives are sda, sdb etc. Partitions are sda1, sda2, sdb1 etc.

Redo drs305's instructions but the last entry does not have a number.

sudo mount /dev/sda5 /mnt <--- number has to be your Ubuntu partition.
sudo grub-install --root-directory=/mnt /dev/sda <--no number at end