Hey Gerrit!

 GK> Interestingly, this never worked reliably for me, neither with MBR
 GK> nor with UEFI. The only safe way is to change BIOS boot order
 GK> settings.

That precludes that the bios recognizes the disk and presents itself as a bootable disk, which in this case is having issues with the nvme disk.  Currently the only repeatable, reliable boot disk is the sata interface.

Also, while I am at it, the 16 boot penguins on a 4k monitor still requires work.

Life is good,
Maurice

... Se ¨e ear gife¨ and eft oftih¨... bysmer he gewyrce¨.
    He who gives and takes it back again does a shameful thing.
--- GNU bash, version 5.1.16(1)-release (x86_64-lilmikii-linux-gnu)