I have the same problem with 2.6.28-11 kernel after today's update (I do updated at least once per day). Booting 2.6.28-10 kernel works.
I am running Kubuntu and I did upgrade with apt-get, therefore I doubt the problem is in update-manager, but it is probably in lower levels (apt, dpkg, initramfs, kernel...).
Also note, that I do not recall any errors during upgrade (beside python-kde4 python-kde4-dev packages that are kept back).
I have the same problem with 2.6.28-11 kernel after today's update (I do updated at least once per day). Booting 2.6.28-10 kernel works.
I am running Kubuntu and I did upgrade with apt-get, therefore I doubt the problem is in update-manager, but it is probably in lower levels (apt, dpkg, initramfs, kernel...).
Also note, that I do not recall any errors during upgrade (beside python-kde4 python-kde4-dev packages that are kept back).