Bug#984426: grub suddenly does not boot and ends up with "grub_register_command_lockdown not found"

[Karsten]

Am 03.03.21 um 18:00 schrieb Colin Watson:
> On Wed, Mar 03, 2021 at 05:20:39PM +0100, Karsten wrote:
>> there was no system update or an installation. It booted perfect.
> Since you're reporting this against grub-pc 2.02+dfsg1-20+deb10u4, and
> since the mentioned grub_register_command_lockdown symbol was only
> introduced in that version, then there must have been a system update,
> because we only released that version yesterday.

A search shows in /var/log/apt/history.log

Start-Date: 2021-03-03  09:28:01
Commandline: /usr/bin/unattended-upgrade
Upgrade: grub-common:amd64 (2.02+dfsg1-20+deb10u3, 2.02+dfsg1-20+deb10u4), grub2-common:amd64 (2.02+dfsg1-20+deb10u3,
2.02+dfsg1-20+deb10u4), grub-pc:amd64 (2.02+dfsg1-20+deb10u3, 2.02+dfsg1-20+deb10u4), grub-pc-bin:amd64
(2.02+dfsg1-20+deb10u3, 2.02+dfsg1-20+deb10u4)
End-Date: 2021-03-03  09:28:36

Start-Date: 2021-03-03  17:03:42
Reinstall: grub-pc:amd64 (2.02+dfsg1-20+deb10u4)
End-Date: 2021-03-03  17:04:12


How can such "unattended-upgrade" be killed?


An upgrade on an other partition to Debian 11 (Testing) failed,
so it is not an good idea to use grub on an failed installation.

> What does "sudo debconf-show grub-pc" say?
>

  grub-pc/install_devices_empty: false
  grub2/device_map_regenerated:
  grub2/kfreebsd_cmdline_default: quiet
  grub-pc/disk_description:
  grub2/force_efi_extra_removable: false
  grub2/update_nvram: true
  grub-pc/install_devices_failed_upgrade: true
* grub-pc/install_devices: /dev/disk/by-id/ata-TOSHIBA_DT01ACA200_84H86A0GS
* grub2/linux_cmdline:
  grub-pc/partition_description:
  grub-pc/hidden_timeout: false
  grub-pc/install_devices_failed: false
  grub-pc/timeout: 5
  grub2/kfreebsd_cmdline:
  grub-pc/kopt_extracted: false
  grub-pc/mixed_legacy_and_grub2: true
  grub-pc/chainload_from_menu.lst: true
  grub-pc/postrm_purge_boot_grub: false
* grub-pc/install_devices_disks_changed: /dev/disk/by-id/ata-TOSHIBA_DT01ACA200_84H86A0GS-part3
* grub2/linux_cmdline_default: quiet