Mender grub integration with grub 2.12 appears broken for Ubuntu and Debian

Board Integrations Debian family
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1

I have a mender-converted Ubuntu 24.04 image. Ubuntu 24.04 uses grub 2.12. The image is bootable with UEFI or BIOS.

The concerning part: I observe that when booting it in QEMU with UEFI, mender updates and, in particular, rollback appear broken. It seems that the bootloader fails to write the mender grubenv variables (bootcount when booting a new update; mender_boot_part and upgrade_available when rolling back).

The interesting part:

  • Booting with BIOS → Everything is fine.
  • Downgrading to grub 2.06 (from jammy) → Everything is fine for both BIOS and EFI.

Does anybody have an idea what is going on here? It sure looks like either a bug (new feature) in grub 2.12 or in the Ubuntu flavor of grub, or in the mender grub integration.

Does anybody have any experience running grub 2.12 with mender integration?

2

I can reproduce the same issue upgrade and rollback with Debian 13 trixie.

  • Debian 12 Bookworm/grub 2.06: BIOS and EFI boot are ok.
  • Debian 13 Trixie/grub 2.12: BIOS is ok, EFI is broken.