Comment 17 for bug 466775

Steven,

The menu.lst in Ubuntu includes defined sections where you can safely include boot entries for other OSes without introducing problems on upgrades. If you instead put these boot entries in the block managed automatically by update-grub, this will invariably cause problems on upgrade. See <https://wiki.ubuntu.com/KarmicKoala/ReleaseNotes#GRUB%20menu.lst:%20install%20the%20maintainer%27s%20version%20vs.%20keep%20the%20local%20version> for more information about this problem.

As for the current boot failure - did you modify your menu.lst using the instructions George gave in <https://bugs.launchpad.net/ubuntu/+source/alsa-driver/+bug/466775/comments/4>? Those boot stanzas are incomplete and should not be used; but you should be able to recover by choosing the older kernel again from the boot menu, and fixing the config fully using the release notes instructions I've linked above.