Repair grub boot settings to work with bcache on a Terra PC by Wortmann AG

I wanted to try bcache, since I have a large HDD and a smaller SSD. I followed these instructions pretty closely:

https://kloppenborg.net/blog/installing-ubuntu-20-04-with-bcache/

Hardware is a Terra PC, from Wortmann AG. Model number: 1009512

I am able to boot from the BIOS boot menu (with the F2 key on this system), but rebooting from the OS drops to a grub shell, without the ability to see the boot partition, or even see the NVME SSD at all. I tried running Boot-Repair, but without seeing any difference.

http://paste.ubuntu.com/p/8M9bmNq8s9/

How to I repair my system, so that can reboot from software ( from the OS's "Power Off / Log Off options in the top right of Gnome, or by issuing sudo shutdown -r on the command line ) ?

Solution 1:

It seems that disabling "Fast boot" in the advanced BIOS settings fixes this problem.