[Bug 1972683] Re: After changing GRUB_DISTRIBUTOR variable grub uses wrong grub.cfg file

[Tony Middleton]

This seems to be a duplicate of 1242417.  However the fix applied for
that bug didn't fix the underlying problem but instead created a
workaround that was sufficient for the case that led to the bug.  It
does not fix the situation reported here.

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Title:
  After changing GRUB_DISTRIBUTOR variable grub uses wrong grub.cfg file

Status in grub2-signed package in Ubuntu:
  New

Bug description:
  An ubuntu system has files in a folder within /boot/efi/EFI and an EFI
  variable both of whose names are given by the GRUB_DISTRIBUTOR
  variable in /etc/default/grub.  By default this is set to "ubuntu".

  I wish to have two ubuntu systems on the same machine so on one of
  them at least need to change GRUB_DISTRIBUTOR to something else.  In
  the past I have done this with two systems "main" and "backup".  This
  worked fine using grub-efi-amd64.

  I have recently tried this on a new system using grub-efi-amd64-signed
  and ended up with an unbootable system.

  After some investigation it turns out that whatever folder within
  /boot/efi/EFI  you boot from it always uses grub.cfg from
  /boot/efi/EFI/ubuntu.

  I can now recreate this at will in virtualbox.  To exhibit this do the
  following steps:

  Do a fresh install of ubuntu in virtualbox.  Check for existence of
  /boot/efi/EFI/ubuntu,  that an EFI entry is shown by efibootmgr and
  that the system reboots.

  Change the value of GRUB_DISTRIBUTOR in /etc/default/grub to "test".
  Run dpkg-reconfigure grub-efi-amd64-signed to trigger grub-install.
  Check for existence of /boot/efi/EFI/test,  that a test EFI entry is
  shown by efibootmgr.  Change nextboot to the test entry and check that
  the system reboots.

  Rename grub.cfg from /boot/efi/EFI/test and reboot from the test
  entry.  Boot should fail,  but it doesn't.

  Restore the test grub.cfg and rename the grub.cfg in
  /boot/efi/EFI/ubuntu.  Reboot from the test entry.  This should work
  OK but it fails.

  This indicates that even when booting from /boot/efi/EFI/test grub is
  using the config file in /boot/efi/EFI/ubuntu

  ProblemType: Bug
  DistroRelease: Ubuntu 22.04
  Package: grub-efi-amd64-signed 1.180+2.06-2ubuntu7
  ProcVersionSignature: Ubuntu 5.15.0-27.28-generic 5.15.30
  Uname: Linux 5.15.0-27-generic x86_64
  ApportVersion: 2.20.11-0ubuntu82
  Architecture: amd64
  CasperMD5CheckResult: pass
  CurrentDesktop: MATE
  Date: Mon May  9 15:59:26 2022
  InstallationDate: Installed on 2022-04-26 (12 days ago)
  InstallationMedia: Ubuntu-MATE 22.04 LTS "Jammy Jellyfish" - Release amd64 (20220419)
  SourcePackage: grub2-signed
  UpgradeStatus: No upgrade log present (probably fresh install)

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