[regression] No access to Ubuntu after installing 12.10 on UEFI system

[YannUbuntu]

Reported by Oz by email.

HOWTO REPRODUCE:

1) Take a GPT/UEFI pc with preinstalled OEM Windows : http://paste.ubuntu.com/1214026

2) Install Quantal in dualboot, and reboot

3) The PC directly boots to Windows. No GRUB have been installed. No GRUB entry in the UEFI firmware. And no grubx64.efi file created in the ESP.

4) Reinstalling grub-efi fails: http://paste.ubuntu.com/1214035
(error: grub-install : source_dir doesn't exist. Please specify --target or --directory )

[Sébastien Bernard (sbernard)]

Try this command to install the grub :
grub-install --efi-directory=/boot/efi/ --target=x86_64-efi --recheck --debug
Where /boot/efi is the directory where the EFI partition (/dev/sda1) is mounted.
I was able to regenerate a grub install with it.
Then run grub by hand in the efi shell.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[YannUbuntu (yannubuntu)]

Thanks Sébastien, your command works on 12.10 (but not on 12.04).

So the problem is that the command is not the same on 12.04 and 12.10:
* 12.04 needs 'grub-install'
* 12.10 needs 'grub-install --efi-directory=/boot/efi/ --target=x86_64-efi'

It would be nice if the same command could be used for both 12.04 and 12.10.