Comment 5 for bug 811485

I'm far from confident about this but running Ubuntu's installer on my machine finally allowed me to boot from a GPT partitioned disk. Not immediately because the installer crashed and although it wiped my EFI system partition, it didn't get around to putting anything else in it afterwards. And even when I copied my backup back, the UUIDs didn't match thus causing trouble for my intact install of linux. But at least I could get to a grub prompt after copying my backed up ESP back. That was a huge improvement. And after fixing the UUID, I have a working installation of linux. (Not of Ubuntu, obviously.)

As far as I can tell, the only thing Ubuntu's installer did which I didn't do was to use fat16 rather than fat32 to format the partition. I am almost certain that my machine would have remained unbootable if it had used fat32.

I found a reference in bug #769669 to a minimum size for the fat32 partition of 256M. That might explain why my machine was not booting. My EFI partition is only 202M. But if that is why, the installer should also insist on a partition which meets that requirement if it switches to fat32 for the EFI partition.

My machine has Phoenix SecureCore Tiano firmware. Version 1.14.

Reference: https://bbs.archlinux.org/viewtopic.php?pid=1024473#p1024473