[Bug 978464] Re: After LTS->LTS (lucid2precise) upgrade, upon reboot drops into grub recovery shell

[Scott Ritchie]

I think the releasing of the update may have exposed another bug, which
counts as a regression:
https://bugs.launchpad.net/ubuntu/+source/grub2/+bug/1009294

-- 
You received this bug notification because you are a member of Ubuntu
Foundations Bugs, which is subscribed to grub2 in Ubuntu.
https://bugs.launchpad.net/bugs/978464

Title:
  After LTS->LTS (lucid2precise) upgrade, upon reboot drops into grub
  recovery shell

Status in “grub2” package in Ubuntu:
  Fix Released
Status in “grub2” source package in Precise:
  Fix Released
Status in “grub2” source package in Quantal:
  Fix Released

Bug description:
  [Impact]
  Any system upgraded from Lucid->Precise is affected, if and only if the user does not opt-in to reinstall grub-pc bootloader during the do-release-upgrade/dist-upgrade nor reinstalls grub-pc into MBR manually before mandatory reboot.

  The affected system will fail to reboot, and will drop into grub shell
  requiring manual boot.

  [Workaround]
  Users should follow the warnings about potential incompatibilities, and reinstall grub-pc into MBR/partitions as appropriate. This will update their grub to a supported version. If users still preffers to keep old grub, we provide Development and Stable Fixes.

  [Development Fix]
  In the Development branch, the fix was to use backwards compatible syntax in grub.cfg. Specifically, using ${var} syntax for variable substitution. (NB! the $var syntax was introduced as fully supported after the grub2 1.98 release, that is after lucid)

  [Stable Fix]
  Patch can be found at: https://code.launchpad.net/~dmitrij.ledkov/ubuntu/precise/grub2/fix-978464/+merge/105844

  [Test Case]
  1) Install/Have already installed: grub-common grub-pc grub-pc-bin grub2-common from lucid (1.98-1ubuntu5)
  2) Make sure version of 1.98-1ubuntu5 of grub2 is used as bootloader, e.g. run  `sudo grub-install /dev/sdX  # Example: sudo grub-install /dev/sda'

  Note: step 1 & 2 can be accomplished by doing a fresh lucid install in
  environment which uses grub-pc, e.g. desktop or server images, but not
  ec2 "cloud" images.

  3) Upgrade grub-common grub-pc grub-pc-bin grub2-common from precise-proposed (1.99-21ubuntu3.1) but do not reinstall grub into MBR. (as part of do-release-upgrade/dist-upgrade select "Yes, continue without reinstalling grub")
  4) Reboot

  Assert True: reboot succeeds.

  To test that bug exists: install grub-common grub-pc grub-pc-bin
  grub2-common from precise (1.99-21ubuntu3) but dot reinstall grub into
  MBR. Rebooting should drop into grub recovery console.

  [Regression Potential]
  Regressions are not anticipated, since only variant of valid syntax is changed. Nonetheless users should see https://help.ubuntu.com/community/Grub2 if they are having troubles booting their system.

To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/grub2/+bug/978464/+subscriptions