My question is similar to that old one here, but which never got a correct answer AIUI:
Boot without starting X-server
But let me restate: Having Raspbian-Pi set up to autostart the X.org desktop (GUI), it is asked how to, while cold booting the Pi, and without prior preparation, nor premeditation of any kind, override
X completely (i.e. boot only to
user/password prompt and command line, at run level 3 in old Linux parlance) just for the one boot in question (no reboot; no persistent changes wanted; just a one-time, unscheduled override).
I assume, if at all possible, it would be done pressing some "magic" key(s) early enough in the boot process, which might have to be authorized beforehand.
So, is there such a way to stop
X from starting?