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Flash PX4 Firmware and Parameters

Flash the PX4 firmware onto the Holybro Pixhawk 6C and upload Bennu's tuned parameter files. This guide covers both the initial firmware flash and the parameter upload workflow.

Prerequisites

  • QGroundControl installed
  • Python dependencies installed: pip install pyserial pymavlink mavsdk
  • Pixhawk 6C connected to your computer via USB

Flash Firmware

The firmware/px4/flash.sh script downloads the correct PX4 firmware for the Pixhawk 6C. Run it from the repo root:

./firmware/px4/flash.sh

To flash a firmware file you already have:

./firmware/px4/flash.sh path/to/firmware.px4

After the script downloads the firmware, choose one of the two methods below.

  1. Open QGroundControl
  2. Go to Vehicle Setup > Firmware
  3. Connect the Pixhawk via USB
  4. Select PX4 Flight Stack and the matching version
  5. Wait for the flash to complete

Option B: Command Line

  1. Connect the Pixhawk via USB

  2. Run:

    python3 px_uploader.py --port /dev/ttyACM0 /tmp/px4_holybro_pixhawk6c_<version>.px4

    This requires px_uploader.py from the PX4-Autopilot source tree.

Upload Parameters

The firmware/px4/upload_params.sh script applies Bennu's parameter files to the flight controller via MAVLink.

Upload All Parameters (default)

./firmware/px4/upload_params.sh

This applies all 6 parameter files in the correct order.

Upload Specific Files

./firmware/px4/upload_params.sh camera_params.yaml tuning_params.yaml

Environment Variables

Variable Default Description
PX4_PORT /dev/ttyACM0 Serial port to Pixhawk
PX4_BAUD 57600 Baud rate for MAVLink

Example with a custom port:

PX4_PORT=/dev/ttyUSB0 ./firmware/px4/upload_params.sh

After uploading, reboot the flight controller to apply changes (power cycle the Pixhawk or send reboot via the MAVLink shell).

Parameter Files

The script applies these files in order from firmware/px4/params/:

File Configures
base_params.yaml Frame type, EKF2, failsafes, battery
motor_params.yaml DShot600 protocol, motor ordering
gps_params.yaml M9N GPS config, compass, geofence
companion_params.yaml TELEM2 at 921600 baud for uXRCE-DDS
camera_params.yaml Distance-based camera trigger every 5 m
tuning_params.yaml PID gains (starting values)

Tuning Parameters

The values in tuning_params.yaml are starting values only. You must tune PID gains in flight using QGroundControl's PID tuning tools. Flying with un-tuned gains can cause oscillation or loss of control.