No boot fallback, no operating system found

[reebderdieb]

I had a tough time getting VanillaOS Orchid to boot. At the end I found that it didn't have the boot option for fallback installed and as such UEFI ignored VanillaOS completely. After pkexec grub-install --removable in host-shell I could finally get it working with bcfg boot add FS1:\EFI\BOOT\BOOTX64.EFI "Vanilla" (Through an EFI-Shell).
Now the HDD even boots from an external case.
The new issue is that I use this external drive also on my laptop where I also installed Vanilla Orchid. Now whatever I do (even selecting the boot file through the laptops EFI boot manager) I always end up on the installed OS.
Did you guys hardcode some partition names, so that no matter what boot file is chosen it picks always the same partition for booting and not the one from the disk itself?
I know it's a special setup, but it worked so far with other distros without any issues.

[reebderdieb]

As mentioned before, got it running at work (Lenovo Thinkcentre) but at home on another machine the BIOS doesn't even see the disk. No matter what I do (disable CMS and secure boot) no chance to get the PC to boot from the disk. Very strange behaviour.