OpenBSD and GRUB

2 January 2007

I got some trouble getting OpenBSD (current) to boot from GRUB (0.97). The GRUB documentation states that you have to use the NetBSD booting instructions, but it does not work. Using:

kernel --type=netbsd /bsd

I got:

/boot too old: upgrade

I was surprised to see that these unofficial quite old instructions were far more useful, although not exactly complete. I confirm it’s not possible to boot directly OpenBSD using the NetBSD way. Even using --type=openbsd which is strangely documented in an other place of the manual. It seems to be an alias for --type=netbsd, though. The answer is chain-loading. The last trick is to use the correct device name for an OpenBSD partition, which I guessed otherwise.

Having an OpenBSD partition using the full second IDE hard drive, the relevant section of /boot/grub/menu.lst should read:

title OpenBSD
root (hd1,a)
chainloader +1

That’s all. So, the GRUB documentation is slightly incorrect and not exhaustive. No big deal.

But, wait… It’s around 7 years this problem exists and hitted people. Maybe it’s a good time to fix up the doc?