grub-install (EFI) is not properly setting the prefix

Bug #632775 reported by Mario Limonciello on 2010-09-07
This bug affects 2 people
Affects Status Importance Assigned to Milestone
grub2 (Ubuntu)
Colin Watson
Colin Watson

Bug Description

Binary package hint: grub2

This is a breakout from bug 632642.

The EFI grub-install is not properly setting up prefix and root. When booted into the EFI system partition, grub starts to load but shows:

error: unknown filesystem.
grub rescue>

Checking the contents of the variables :

prefix was set to (hd1,gpt1)/boot/grub
and root was set to hd1,gpt1

I think these should both be (hd1,gpt2) and hd1,gpt2 respectively since the modules and conffile do not live on the EFI system partition.

Changed in grub2 (Ubuntu):
assignee: nobody → Colin Watson (cjwatson)
Colin Watson (cjwatson) wrote :

00:51 <cjwatson> I think this is going to need something a bit like, only for EFI
00:52 <cjwatson> specifically the bit that handles a partition-only prefix "drive"
00:52 <cjwatson> the alternative is hardcoding the entire prefix device, which is seriously undesirable
00:53 <cjwatson> then the EFI grub-install will have to find the partition number for /boot/grub and hardcode that but make sure to leave out the drive

Changed in grub2 (Ubuntu):
status: New → Triaged
importance: Undecided → High
Changed in grub2 (Ubuntu Maverick):
milestone: none → ubuntu-10.10
Manoj Iyer (manjo) wrote :

Logs from server install of Ubuntu on Weybridge with UEFI. I did not see any grub-efi error on install but on boot from HDD I got grub rescue> prompt.

Colin Watson (cjwatson) wrote :

I've sent a couple of patches upstream for review.

Changed in grub2 (Ubuntu Maverick):
status: Triaged → In Progress
Launchpad Janitor (janitor) wrote :

This bug was fixed in the package grub2 - 1.98+20100804-4ubuntu5

grub2 (1.98+20100804-4ubuntu5) maverick; urgency=low

  [ Colin Watson ]
  * Make grub-efi-amd64 conflict with grub-pc as well as the other way round
    (LP: #632642).
  * Extend EFI initialisation code to understand (,$partition)-style
    prefixes. If the EFI System Partition is on the same disk as
    /boot/grub, use this rather than allowing GRUB to set the prefix to the
    EFI System Partition by default (LP: #632775). (If they're on different
    disks, grub-install already used a UUID to find /boot/grub.)

  [ Mario Limonciello ]
  * Modify ubuntu_efi_install to check for case-insensitive EFI distributor.
    (LP: #632706)
 -- Colin Watson <email address hidden> Wed, 08 Sep 2010 13:41:18 +0100

Changed in grub2 (Ubuntu Maverick):
status: In Progress → Fix Released
AnrDaemon (anrdaemon) wrote :

It seems I have this issue (not as drastic, the installer works... somewhat) with 12.04-a2 CD image.
Trying to boot it in VirtualBox in EFI mode, the message

error: "prefix" is not set

appears briefly, then replaced by "GNU GRUB" menu with 3 usual entries (LiveCD/Install/Check for defects).

Ajeet (ajeetraina) wrote :

Any fix for Natty? I encountered the issue on physical hardware during UEFI mode selection with the same error :

error: "prefix" is not set

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