Block reverse from Mission Planner. I’m wondering if this could be accomplished with setting the Servo max/Min/Trim settings. I’ll try something out on the bench.
Bad AHRS could just be a poor GPS reception indoors. Take it outside and see if it clears.
GPS is not calibrated. Accels can be done with the Pixhwawk on the bench in 3-axis then when it’s in the boat level it and then use the 1 axis calibration. Compass cal just spin the boar around a few axis using a long USB cable.