Matek F405 CTR + M8Q-5883: no GPS or compass data

I’m trying to setup an F405 CTR and GPS/compass module. I’m running copter 4.0.3 using the MatekF405 target. I’ve wired up the compass+GPS as shown here under the iNav instructions (Serial using tx/rx4). Serial3/4_Protocol are set to GPS.

The GPS module powers on and I quickly get a blinking blue LED on the GPS indicating signal fix. However in Mission Planner / QGC I get 0 satellites and no other GPS info, and the compass reports as “not healthy” and will not calibrate (bar never grows). Any ideas what’s going on?

Hi @npyoung - have you managed to solve this problem? I face something similar…