I just tried upgrading our Ubuntu EC2 server to 12.04 from 11.10, and it halts on several package upgrades, starting with memtest86+. CTRL+C is the only way out, and in the end there is the following error:
Errors were encountered while processing: memtest86+ ubuntu-standard grub-legacy-ec2 grub-pc friendly-recovery linux-image-3.2.0-24-virtual python-apport linux-image-virtual linux-virtual apport
Any advice on what went wrong and how to fix it?
UPDATE: Turns out to be a problem with GRUB, though I still don't understand what is going wrong. Why is GRUB used with EC2 at all?