Matek F405-STD BN-880 Magnetometer not working

[Paschwuerfler]

I have a Matek F405-STD with an BN-880 running the latest inav for the Matek F405.
The GPS is getting a position, but the magnetometer is not recognised.
I tried adding pull-up resistors to the i2c bus, but it didn't help.
Also: When i add the GPS, the baro indicator goes red, which leads me to believe that they might share the bus.
What can i do now ?
Can i emulate an 2c bus ?
I can't find anybody having the same issue....

[Paschwuerfler]

turns out the only thing not working is my brain - magnetometer not enabled in configuration......