Comment 4 for bug 414943

> It looks like you manually edited the menu.lst file and put the hardy kernel there.
Yes, I edited menu.lst. I didn't actually put the hardy-kernel line there, but I did have to make lots of changes to accomodate my 2-disk dual-boot configuration.

> I agree that there should be a warning though.
Yes, agreed. The bootup with an old kernel, but an otherwise newer OS, creates a hard-to-diagnose situation where the system mostly works but has lots of tricky bugs. It's OK to give a warning rather than actually refuse to boot.

This bug may be a matter more for grub than update manager, as the warning should be issued whether or not update-manager edited menu.lst