Any luck on your end? I am having the same problem. Slot C is designed for it and Meshtastic says Slot C is supported for the GPS module. I am not getting it to register. I’ve tried two GPS modules.
i am having several rak19003 models,
one running a gps 1210, and an other one running a gps 12500
both are in the same slot, and functional. firmware 2.2.23 atm
before it was 2.2.10
if i remember correcty, there was only one slot, where the modules (and screws) did fit in. that one i used,
after the last update, the modules needed quite some time to start functioning, i think there was a gps reset involved in the last update. i thought its no more working, but then i just let it outside for several hours and suddenly it worked…