Sorry, ignore that. Just found the culprit. It was a botched audio CD in the drive that was trying function as a bootup disc for some reason. I've now taken the CD out and the problem's gone. As this looks like a BIOS issue instead of grub issue, I guess this bug can be closed as not a bug after all.
** Changed in: grub2 (Ubuntu) Status: New => Invalid -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/703241 Title: Crash on alternate bootups before grub2 menu reached -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs