Pixhack Ardupilot load failure

Hello and thank you for reading.

I have 3 Pixack controllers. One of them simply refuses to run on Ardupilot and I can only get PX4 to work correctly.

Ardupilot loads, the boot sounds plays, but after that nothing. LED does not flash and when connecting to Mission planner I get a “timeout” and then “no heartbeat” messages.

When installing PX4 everything works fine again.