@landley yeah, basically I'm looking for a stage 1 thingy that BIOS can see as bootable device and that allows to do the usual "yeet kernel+initramfs into ram and floor it".
- Kinda "#BootROM" similar to #OptionROM|s...
Worst-case I could just look for some sort of #SATA-DOM / -Board that offers a hardware write protection or can do #readonly #Flash instead...