Pixhawk 6C Supported Firmware

Pixhawk 6C ships with PX4 FMUv6C Firmware

PX4
Pixhawk 6C is supported on PX4 1.13.1 release and later.

Ardupilot
Pixhawk 6C is supported in Ardupilot 4.2.3 stable release and later. Firmware can be flash via Mission Planner or QGroundControl. It can also be downloaded here: https://firmware.ardupilot.org/

QGroundControl
Must use QGC v4.2.4 or later, or Daily QGC Build.