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

[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.

> I simply switched the PC off and the next time it does not boot any more!
> Every entry of the boot menu ends up with the attached screenshot.
> 
> To recover the PC i had to boot an Debian 10 installation from SD-Card and select recover of grub.
> 
> I have no idea if this is reproducible and the search for such an error is empty.
> So i report it here, if someone has the same error.

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

-- 
Colin Watson (he/him)                              [cjwatson at debian.org]