Pixhawk 6X — AUX Outputs Not Working in Mission Planner (SERVO9+ Disabled)

I’m working on a VTOL project using a Pixhawk 6X with ArduPlane firmware. Everything works fine on the MAIN outputs (SERVO1–SERVO8), but all AUX outputs (SERVO9 and above) are disabled in Mission Planner — I don’t even get the green PWM sliders.

:white_check_mark: What I’ve Tried:

  • Set SERVO_GPIO_MASK = 0
  • Set BRD_IO_ENABLE = 1
  • Set Q_ENABLE = 1
  • Verified OVERRIDE_CHAN = 0
  • BRD_SAFETYENABLE = 0 (safety button bypassed)
  • Disabled all GPIO usage
  • Assigned valid functions (motors, servos) to SERVO9_FUNCTION through SERVO14_FUNCTION
  • Uploaded a clean .param file with full VTOL mapping (includes tilt motors and V-tail control surfaces)

:wrench: Firmware Context:

  • Pixhawk 6X
  • ArduPlane v4.4.x
  • On firmware 4.2 and later, BRD_PWM_COUNT no longer exists, so I couldn’t use it to enable PWM on AUX outputs.
    • I’m aware that now we use SERVOx_FUNCTION = -1 to make a pin a GPIO, and we can use SERVO_GPIO_MASK if needed (which is already set to 0 in my case).

:red_question_mark: My Issue:

  • No matter what functions I assign to SERVO9–SERVO14, the AUX outputs remain completely disabled.
  • No signal, no PWM activity, nothing in Mission Planner (no green bars).
  • Could this be specific to the Pixhawk 6X hardware? Or maybe something firmware-related?

Any help or suggestions would be greatly appreciated!

Thanks :folded_hands: