Comment 11 for bug 420933

I noticed that after an initial installation of Karmic in kvm, the first (warm) reboot spends ages scanning the CD, but subsequent reboots are fine. This is a bit perplexing.

It might be worth putting 'set debug=disk' at the top of /boot/grub/grub.cfg to see what disk it's looking at. The 'set debug=all' that Dean already tried is not without use, but it all scrolls past so quickly that it's hard to see what's going on.