I had a scan through the forum, but still at a loss.
My laptop used to work fine. Windows has it's own partition, and Manjaro's root was installed on another with the bootloader (dev/sda8). Everything was fine, but now on boot, the screen is black with only the word 'GRUB' on it.
I've tried mounting:
sudo mount --bind /dev /mnt/dev
and then chroot /mnt to reinstall GRUB with sudo , but there are errors:
/proc/devices: fopen failed. No such file or directory, and then errors about the partition not having a BIOS boot partition, embedding is not possible, and it will not proceed with blocklists.
The laptop has legacy options on, and it worked for weeks, until today. I even ran a full reinstall with format options on dev/sda8, still the same problem.