Comment 6 for bug 235638

It is fairly common to have small /boot partitions at the start of a disk, so the probability of kernel upgrades filling up /boot is significant.
Kernel upgrades should warn of this and offer to uninstall the oldest image to make space?
The Ubuntu installer should warn if a /boot partition is too small?
I had the same problem with one of my 50MB /boot partitions. The upgrade error messages did not indicate the problem, but those from "sudo dpkg --configure -a" did.