Comment 127 for bug 1065281

Aha, got it: the efidisk module is working but the FAT file system support isn't quite right, so it's just the EFI System Partition that GRUB has trouble reading. The missing commit is this one, which is in 2.00 thus explaining why this works in more recent releases:

  http://git.savannah.gnu.org/gitweb/?p=grub.git;a=commitdiff;h=daa59f47f6818d2a2c90526be5b2b38a11770dc1

Doing a full boot loader test is awkward due to the involvement of a signed image, but I've confirmed the bug with grub-fstest and grub-mount, and built versions of those tools with that patch which can successfully read all the files under /EFI/ubuntu/. I'll prepare a backport.