What I still need to figure out is how I can replace init with a custom process... but I think for that I will have to patch init itself.Why do you need to patch init?
I'm not sure if I really have to but I don't want to run all init scripts of the new system right away but do some other stuff. Would be nice to put the whole system back into the state of the early initramfs phase. But perhaps some workaround with init is sufficient. I'll do some research on that topic.
Thx, for your help with the pivot_root issue! K. Haselhorst