Compass calibration works on Plane but not on Rover - Mateksys F405-Wing

Hi, I have a clean Mateksys f405-wing and the compass m8q-5883 wired as described on ardupilot site for this board. When installing rover compass calibration does not do anything, when installing plane or copter firmware calibration begins and ends. Now I want to build a boat and hence rover would be much better. What can I check to find out why compass calibration triggered from mission planner via usb does not do anythign on rover (the green bar does not appear, nothing)? Regards, Marcus from Heidelberg, solar boat

Is the Rover disarmed?

yes, rover is disarmed.