I have a dual boot system with Pop OS 20.04 and Windows 11 on the same 500GB SSD. I installed GRUB to make this work instead of using systemd bootloader, and everything worked smoothly for over a year, until I updated packages on Pop a few days ago.
Suddenly, rebooting gave me a black screen with the GRUB CLI. I was able to follow instructions given here to manually boot, but I had to do this every single time. To fix this, I got an Ubuntu 20.04 live USB and ran boot-repair from it, with the recommended settings. This appeared to run smoothly and said it reinstalled GRUB. Even after this, rebooting led me to the same CLI. I can confirm that boot-repair did something because I now had to manually boot with the efi directory under (hd2,gpt7)
whereas it was earlier in (hd2,gpt8)
.
Here are the logs generated by boot-repair. It also showed this -
Which as far as I can tell, seems unrelated to my problems. The UEFI boot order seems to be right and has "pop" at the top. The other options lead to either just Pop or just Windows booting.