Grub menu not readable / old configuration always chosen

[rolfschr]

Describe the bug

I'm running NixOS 22.11. Recently, I saw that the Grub menu looks strange (way to big, not fully readable). I think this might be related to connecting an external monitor to the laptop. Upon further inspection, I also realized that there is always one specific generation set as the default value for Grub. Even when running nixos-rebuild switch/boot, the old generation stays. I can't seem to delete it neither.

Steps To Reproduce

🤷

Expected behavior

When running nixos-rebuild switch, a new configuration is installed as the default option in Grub

Screenshots

Generation 32 is always chosen:

Trying to delete the old generation doesn't work. It did work with the pre-32 generations (not visible in the screenshot). I made sure I'm running a non-32 generation when garbage-deleting (not sure if this matters).

Additional context

This is a Thinkpad. I have recently setup a docking station with an external monitor connected. It worked fine out of the box. I had the laptop screen lid closed and only used the external monitor. Sometimes, I would use the laptop without the docking station. Going back and forth didn't cause any issue. 1-2 days ago, I updated the channels and did a general system update (sudo nix-channel --update; sudo nixos-rebuild switch; sudo nix-env -u '*'). I think the unreadable Grub menu has been there before but I'm not sure. The next time I connected the laptop to the docking station, the external monitor was now an 'empty' desktop (i.e. no taskbar, desktop icons, etc.). I realized it was not used as the only monitor but as an additional one (as if the lid was open). I could not change the desktop configuration (same issues as in #11244 / #12331). I then tried to rollback to a previous generation with no luck (i.e. desktop issue stays the same).

At some point, I had the nixos-unstable channel in the repository but removed it.

This is just for additional context to explain the journey.

Notify maintainers

@samueldr

Metadata

Please run nix-shell -p nix-info --run "nix-info -m" and paste the result.

[user@system:~]$ nix-shell -p nix-info --run "nix-info -m"
 - system: `"x86_64-linux"`
 - host os: `Linux 5.15.94, NixOS, 22.11 (Raccoon), 22.11.2720.50c23cd4ff6`
 - multi-user?: `yes`
 - sandbox: `yes`
 - version: `nix-env (Nix) 2.11.1`
 - channels(root): `"nixos-22.11"`
 - channels(rolf): `""`
 - nixpkgs: `/nix/var/nix/profiles/per-user/root/channels/nixos`

[rolfschr]

I found this systemd issues that describes precisely the situation. The proposed solution ("run bootctl set-default "" to delete the default EFI var ") worked: I was able to delete the config generation 32 and now upon nixos-rebuild switch, any new config gets chosen per default as expected.