I currently have a Pixhawk installed on an Actobotics Nomad. I uploaded the Rover firmware (v3.1.1) through Mission Planner. I enabled Skid Steering through the Basic Parameters Tab. I am using a Futaba T10J with a FrySky Delta 8 receiver which is outputting CPPM. Calibrated the compass, accelerometer, RC input and modes. Went through all the recommended initial setup.
When I initially tried to arm the Pixhawk by holding the Throttle centered and then Steering hard right (as suggested in the documentation), it didn't arm at all. I then disabled ARMING_CHECK, guessing that it wasn't able to get through one of the checks. And yet it still won't arm. I disabled the Safety Switch to see if that would help and again it won't arm. So I disabled SKID STEERING (IN and OUT) and now it arms with the throttle down at about 1100 and steering hard right. However it does not disarm, with the throttle at 1100 (LOW) and steering hard left. It still does not arm in the Skid Steer mode, which is essential for this chassis, which doesn't have traditional steering.
A few additional things to note. I tried a different receiver and transmitter setup (DX6i with R615X receiver) and the same problem persisted. I uploaded Quadcopter firmware through Mission Planner to see if the arming issue was present with other types of firmware. With the Quad Firmware, the board armed with absolutely no issues whatsoever.
I am new to the Pixhawk platform and any help would be greatly appreciated. I've tried to methodically troubleshoot this for the last week and have hit a dead end.