I believe a default change is needed before this would work:
1. Install and update Lucid on a VM
2. Note output of false from `sudo debconf-show grub-pc | grep empty
3. Run "sudo dpkg-reconfigure grub-pc". Note how it doesn't let you Select No. (looks to be bug 580408)
4. Note how _empty is now true.
5. Upgrade to 12.04.
6. During upgrade if _empty is set to true no grub prompt loads. If a prompt does load, selecting to not install grub will be equivalent for the next breakage.
7. Upgrade to 14.04 and reboot. Note how it doesn't ask you any questions at all about Grub.
8. Find blinking cursor and broken grub.
I believe a default change is needed before this would work:
1. Install and update Lucid on a VM
2. Note output of false from `sudo debconf-show grub-pc | grep empty
3. Run "sudo dpkg-reconfigure grub-pc". Note how it doesn't let you Select No. (looks to be bug 580408)
4. Note how _empty is now true.
5. Upgrade to 12.04.
6. During upgrade if _empty is set to true no grub prompt loads. If a prompt does load, selecting to not install grub will be equivalent for the next breakage.
7. Upgrade to 14.04 and reboot. Note how it doesn't ask you any questions at all about Grub.
8. Find blinking cursor and broken grub.