Followed ax2mx's instructions (thx) - also the reminder about the app for activating by f.lucadetena came in really handy (thx too).
However, if I re-enable the csrutil (aka SIP) and reboot out of Recovery-mode, the device appears to be disconnected from cable.
Ideas?
I can now live without SIP function, but I rather keep it on, if possible?
Thanks!!