Here’s the process:

Use efibootmgr to remove all boot messages.

$ efibootmgr
BootCurrent: 0000
Timeout: 5 seconds
BootOrder: 0000,2001,0002,2002,2003
...
$ # now take the IDs from the BootOrder line and remove each of them using the following commands
$ efibootmgr -b 0000 -B
$ efibootmgr -b 2001 -B
$ efibootmgr -b 0002 -B
$ efibootmgr -b 2002 -B
$ efibootmgr -b 2003 -B

This tells your EFI system that there are no EFI entries to boot into. Don’t worry, this will get repopulated later.

Remove /boot/EFI/ and /boot/grub/

To remove all EFI boot images and all grub configurations, run the following command:

# rm -rf /boot/EFI/ /boot/grub/

Re-install grub

Re-install the GRUB bootloader, along with its config files.

# grub-install --efi-directory=/boot
# grub-mkconfig -o /boot/grub/grub.cfg

Conclusion

This should fix the issue, since it clears out all grub and EFI entries. I had to re-install grub through my package manager, and change a few settings that I had set up for FDE. If this is helpful, you can let me know by sending me an email, by contributing to a project I work on, or sponsoring me to work on open-source technology.

Happy GRUB hacking!