After using grub-customizer, how do I recover the ZFS Grub2 menu options on Ubuntu 20.04?

After using grub-customizer for a bit (which I now know is a bad idea), my grub menu looks very different from the default. It's missing the history menu, which contains snapshots, and some of the entries that are supposed to be inside it are in the main menu:

Artix is on /dev/sda1, and Ubuntu is on /dev/nvme0.

How can I restore the default, which has the following four entries?

• Ubuntu 20.04.2 LTS
• Advanced options for Ubuntu 20.04.2 LTS
• History for Ubuntu 20.04.2 LTS
• UEFI Firmware Settings

Edit: I restored using the backup that grub-customizer created, but the history entries are still missing.

1 Answer

I got it fixed by doing the following

1. purging grub-customizer.
2. restoring a backup of the grub configuration files from /etc/grub.d/backup/, where grub-customizer put it.
3. Running grub-mkconfig -o /boot/efi/EFI/ubuntu/grub.cfg to regenerate grub
4. reinstalling zsys and the grub2 efi x64 package.

After this, everything is back to normal.