[Bug 1901633] Re: GRUB doesn't load/save values when a submenu entry is used

[Kellen Renshaw]

My customized (via 40_custom) grub.cfg that displays the values of
initrdfail (amongst others).

** Attachment added: "grub.cfg"
   https://bugs.launchpad.net/ubuntu/+source/grub2/+bug/1901633/+attachment/5427642/+files/grub.cfg

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Title:
  GRUB doesn't load/save values when a submenu entry is used

Status in grub2 package in Ubuntu:
  New

Bug description:
  It appears that GRUB in focal (2.04-1ubuntu26.6) doesn't load or save
  values to grubenv when using entries that are under a submenu. This is
  similar to LP #1816633

  For context, this issue arose using the latest focal cloud image
  (https://cloud-images.ubuntu.com/focal/current/focal-server-cloudimg-
  amd64.img). I attempted to set GRUB_DEFAULT to "1>0" to boot the first
  entry of the "Advanced options for Ubuntu" submenu as a test for
  booting a specific kernel version.

  This resulted in a boot loop where the first entry in the submenu was
  booted, the kernel panics, and restarts.

  Using GRUB_DEFAULT=0 results in a boot > panic > boot > success. This
  is similar to LP #1870189.

  From LP #1870189, cloud images set the GRUB_FORCE_PARTUUID variable in
  /etc/default/grub.d/40-force-partuuid.cfg. This results in menu
  entries that use a if/else structure to attempt initrd-less boot
  before falling back to booting with an initrd. The if/else structure
  uses a GRUB variable called initrdfail (and I believe recordfail) to
  note whether the initrd-less boot worked.

  Note that unsetting GRUB_FORCE_PARTUUID works around my issue, since
  the if/else logic that uses the initrdfail variable is only placed in
  the grub.cfg when GRUB_FORCE_PARTUUID is set.

  However, I tried using custom menuentries in grub.cfg to show the
  variables' state in an attempt to determine why this didn't work with
  GRUB_FORCE_PARTUUID set. I will attach it to this bug.

  This showed that the submenu menuentries didn't set or use the
  variables, specifically initrdfail and recordfail. The first entry,
  before the "Advanced options..." submenu, did set the variables, and
  would use them. However, using that first entry (by booting it once,
  getting the kernel panic and restarting) to set initrdfail to "1"
  didn't work. The submenu menuentries booted as though the value was
  unset.

  I tested this by manually selecting boot entries and observing the
  values printed by my custom menuentries.

  I expected that the submenu menuentries would use the values and would
  set them appropriately.

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