I finally tried rebooting the affected server, and as I expected it wouldn't boot with 'no bootable device available', and I was able to recover it by upgrading (admittedly ancient) BIOS (EFI) to the latest available version.
-- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1855574 Title: grub-efi-amd64-signed (1.93.15+2.02-2ubuntu8.14) failed to upgrade, system unbootable To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/efibootmgr/+bug/1855574/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
