Initializing the Flight Controller#

What you will need

  • A base station computer (Linux recommended; macOS works with brew install dfu-util)

  • Flight Controller

  • USB to USB-C cable

What you will get

  • An up-to-date, initialized Flight Controller running PX4

The Flight Controller (FC) implements several low-level behaviors, e.g., stabilizing the Duckiedrone around roll, pitch, and yaw through three different PID controllers. Correctly configuring the Flight Controller is critical for flying safely.

The DD24 runs the PX4 Autopilot firmware, built for the mamba-f405-mk2 target. Flashing is performed entirely from the command line with dfu-util so that the procedure is fully scriptable and does not require a graphical flasher.

Note

The flashing is a two-stage process:

  1. Flash the PX4 bootloader (the omnibusf4sd_bl bootloader, which is the canonical bootloader for STM32F405-based boards using PX4 board ID 42, including the Diatone Mamba F405 MK2).

  2. Flash the PX4 firmware built for the mamba-f405-mk2 target on top of the bootloader.

Both stages are performed via dfu-util while the FC is in STM32 DFU mode.

1. Install dfu-util#

Connect the flight controller to a laptop running Ubuntu and update the package list:

sudo apt update
sudo apt install dfu-util

Tip

Use dfu-util version >= 0.9. Older versions may silently truncate writes on STM32F4 targets.

(Optional but recommended) install a udev rule so dfu-util does not need sudo:

sudo tee /etc/udev/rules.d/45-stm32-dfu.rules > /dev/null <<'EOF'
SUBSYSTEM=="usb", ATTR{idVendor}=="0483", ATTR{idProduct}=="df11", MODE="0664", GROUP="plugdev"
SUBSYSTEM=="usb", ATTR{idVendor}=="26ac", MODE="0664", GROUP="plugdev"
EOF
sudo udevadm control --reload && sudo udevadm trigger

2. Enter DFU Mode#

  • Disconnect the USB cable connecting the Flight Controller to the Raspberry Pi.

  • Reconnect it to your base station while keeping the BOOT button on the side of the flight controller pressed.

../_images/speedybee-boot-button.png

Fig. 49 Flight controller BOOT button location.#

  • After a couple of seconds, release the BOOT button.

  • Verify that the board is enumerated as an STM32 DFU device:

dfu-util -l

You should see one or more interfaces with the vendor/product ID 0483:df11 (“STMicroelectronics STM Device in DFU Mode”), as in the following image:

../_images/dfu-util-devices-list.png

Fig. 50 Output of dfu-util -l with the FC in DFU mode.#

3. Flash the PX4 Bootloader#

Download the prebuilt omnibusf4sd_bl bootloader hex shipped with the PX4 user guide and convert it to a raw binary that dfu-util can flash:

sudo apt install binutils-arm-none-eabi   # provides arm-none-eabi-objcopy
curl -L -o omnibusf4sd_bl.hex \
  https://github.com/PX4/PX4-user_guide/raw/main/assets/flight_controller/omnibus_f4_sd/omnibusf4sd_bl_d52b70cb39.hex
arm-none-eabi-objcopy -I ihex -O binary omnibusf4sd_bl.hex omnibusf4sd_bl.bin

Tip

The bootloader hash suffix d52b70cb39 is tracked in the PX4 user guide; if the URL above 404s, re-resolve it from the PX4 bootloader-from-Betaflight page. You can also build the bootloader from source with make omnibusf4sd_bl from a clone of PX4/PX4-Bootloader.

With the FC still in DFU mode, flash the bootloader to address 0x08000000:

dfu-util -a 0 --dfuse-address 0x08000000:leave -d 0483:df11 -D omnibusf4sd_bl.bin

Tip

Explanation of the dfu-util command:

  • -a 0: selects the first DFU alternate setting (the internal flash).

  • --dfuse-address 0x08000000:leave: writes to the start of flash and reboots the board into the freshly written image after the write completes.

  • -d 0483:df11: matches the STM32 ROM DFU device.

  • -D omnibusf4sd_bl.bin: the file to flash.

After the flash completes (this takes a few seconds), the board will reboot. It will now enumerate as a PX4 bootloader device — you can verify with lsusb (the device will show up under the 26AC USB vendor ID, e.g., 26AC:0011) or by listing serial devices:

ls /dev/serial/by-id/    # should list a *PX4_BL* entry

4. Flash the PX4 Firmware#

Download the PX4 firmware binary for the mamba-f405-mk2 target:

curl -L -O https://github.com/duckietown/duckiedrone-px4-driver/releases/latest/download/diatone_mamba-f405-mk2_default.bin

Put the FC back into DFU mode (disconnect, hold BOOT, reconnect), confirm it shows up again in dfu-util -l, then flash the firmware to the application offset 0x08008000:

dfu-util -a 0 --dfuse-address 0x08008000:leave -d 0483:df11 -D diatone_mamba-f405-mk2_default.bin

Important

The PX4 firmware is loaded at offset 0x08008000, not at 0x08000000. The first 32 KiB of flash is reserved for the bootloader you wrote in step 3. Writing the firmware to 0x08000000 would overwrite the bootloader.

After the flash completes the board reboots and runs PX4. The boot sequence is: STM32 reset → PX4 bootloader at 0x08000000 → PX4 firmware at 0x08008000.

Tip

Alternative — use the PX4 serial uploader.

Once the bootloader is flashed (step 3), you can also flash the firmware over USB-CDC with the PX4 uploader script. This is the canonical PX4 path — it verifies that the firmware’s board ID matches the bootloader’s reported board ID before erasing flash:

git clone --depth 1 https://github.com/PX4/PX4-Autopilot.git
python3 PX4-Autopilot/Tools/px4_uploader.py diatone_mamba-f405-mk2_default.px4

Use this approach if you have the .px4 file (a JSON-wrapped, board-ID-tagged firmware envelope) instead of the raw .bin. The dfu-util flow above is preferred for fully programmatic deployments.

5. Starting the drone software stack#

Now you will need to start the drone software stack, allowing you to connect to the flight controller from your laptop.

To do so you need to use the Duckietown shell dts.

Attention

Make sure that the dts on your laptop is:

  • Running the ente distribution. You can check by running dts profile list

  • Updated to the latest version by running:

    dts update

To start the flight software stack execute the command

dts duckiebot update -t duckiedrone --distro=ente -f [ROBOT_NAME]

Wait for the command to terminate before proceeding to the next step.

6. Connecting to the Flight Controller#

Attention

Unplug the battery from your drone!

Installing QGroundControl and Restoring the correct parameters#

By following these steps you will be able to install QGroundControl, connect to your flight controller via TCP, and restore your vehicle’s parameters from a .params file. The .params file contains the PX4 parameters that differ from the upstream defaults (rangefinder-only altitude estimation, quadrotor airframe configuration, controller tuning, etc.). You can download it from this link.

  1. Install QGroundControl:

    • Go to the QGroundControl website and download the installer for your operating system (Windows, macOS, or Linux).

    • Follow the installation instructions for your OS:

      • Windows: Run the installer and follow the prompts.

      • macOS: Download the .dmg file, open it, and drag the QGroundControl icon into your Applications folder.

      • Linux: Follow the package manager or AppImage instructions provided on the QGroundControl download page.

    • Once installed, launch QGroundControl.

  2. Connect to Your Vehicle via TCP:

    • Open QGroundControl on your computer.

    • Go to the Application Settings → Comm Links section by clicking on the Q application icon in the top left corner.

    • Select Add to create a new communication link.

    • Choose TCP from the dropdown.

    • Set the Host Address to <robot_name>.local and the Port to the port exposed by the mavlink-proxy service on your Duckiedrone (default: 5760).

    • Click Connect to establish the connection with your flight controller.

  3. Access the Vehicle Setup:

    • Once connected, open the menu by clicking on the Q application icon in the top left corner and open the Vehicle Setup page from the popup menu that appears.

  4. Navigate to Parameters:

    • In the Vehicle Setup menu, select the Parameters tab to view the configurable parameters for your vehicle.

  5. Load the .params File:

    • In the Parameters screen, click on the Tools menu in the top right corner.

    • Select Load from file… from the dropdown menu.

    • Browse to the location of your .params file on your computer, select it, and click Open.

  6. Apply the Parameters:

    • QGroundControl will load and apply the parameters from the file to your vehicle. Progress indicators or messages will confirm that the parameters are being applied.

  7. Reboot the Vehicle:

    • After loading the parameters, it is usually necessary to reboot the flight controller for changes to take effect.

    • You can reboot the vehicle by selecting Reboot Vehicle from the Tools menu.

Additional Tips#

  • Multiple Loads: Some parameters may require multiple loads until they are all applied correctly.

  • Check for Errors: Ensure QGroundControl does not report any errors during the parameter loading process.

  • On-board calibration is mandatory: the shipped .params file deliberately omits all CAL_* (accelerometer/gyro/magnetometer/barometer calibration) entries because those are tied to a specific board’s sensor IDs. Run the Sensors calibration in QGroundControl on the actual flight controller after loading the parameters.

Troubleshooting#

Troubleshooting

SYMPTOM

dfu-util shows no devices.

RESOLUTION

The FC has not entered DFU mode. Disconnect USB, hold the BOOT button while reconnecting, then run dfu-util -l again. On Linux, also confirm there is no kernel driver claiming the device (e.g., ModemManager) by checking dmesg after plug-in.

Troubleshooting

SYMPTOM

After flashing, the board does not enumerate as a PX4 bootloader.

RESOLUTION

The most common cause is that the firmware was flashed to 0x08000000 instead of 0x08008000, overwriting the bootloader. Re-enter DFU mode and re-run step 3 to restore the bootloader, then re-run step 4 with the correct address.

Troubleshooting

SYMPTOM

px4_uploader.py reports “expected board ID 42, got X”.

RESOLUTION

The wrong bootloader was flashed in step 3. Re-flash omnibusf4sd_bl.bin (board ID 42 matches the mamba-f405-mk2 PX4 target).

Troubleshooting

SYMPTOM

I am having issues following the instructions!

RESOLUTION

We’re happy to support and to hear your feedback! Please post a question on our StackOverflow, you can find the instructions on how to join it here.

You can also contact us via Slack at the following channel: duckietown-sky-help