Comment 62 for bug 8497

richard (richardjones) wrote :

This is STILL an issue in GUTSY and can create an UN-BOOTABLE SYSTEM that's very difficult to debug.

Ubuntu (or grub) simply doesn't have the same idea of disk ordering as the BIOS.

In particular this is what just happened to me with a new Gutsy install.

After installation and reboot the computer just said "Grub stage 1.5" and "Error 15". That error apparently means it couldn't parse a number, which is pretty much a useless error.

After spending about 2 hours on the problem, I realised that grub had installed itself on hd0, according to Ubuntu, but actually the second disk according to the BIOS. The computer was happy to boot from the second disk, but when grub then ran I can only assume it thought it was on the first disk and subsequently read information from that disk which didn't have the grub-stuff installed. And it broke.

I made it all work by physically shifting the disk connections around to make the boot disk was the first in the BIOS sequence (but detected as *hd2* by Ubuntu) and reinstalling (just to be sure).