UAVCAN Firmware Upgrading

Vectorcontrol ESC Codebase (Pixhawk ESC 1.6 and S2740VC)

Download the ESC code:

git clone
cd vectorcontrol

Flashing the UAVCAN Bootloader

Before updating firmware via UAVCAN, the Pixhawk ESC 1.6 requires the UAVCAN bootloader be flashed. To build the bootloader, run:

make clean && BOARD=px4esc_1_6 make -j8

After building, the bootloader image is located at firmware/px4esc_1_6-bootloader.bin, and the OpenOCD configuration is located at openocd_px4esc_1_6.cfg. Follow these instructions to install the bootloader on the ESC.

Compiling the Main Binary

BOARD=s2740vc_1_0 make && BOARD=px4esc_1_6 make

This will build the UAVCAN node firmware for both supported ESCs. The firmware images will be located at com.thiemar.s2740vc-v1-1.0-1.0.<git hash>.bin and org.pixhawk.px4esc-v1-1.6-1.0.<git hash>.binn.

Sapog Codebase (Pixhawk ESC 1.4 and Zubax Orel 20)

Download the Sapog codebase:

git clone
cd sapog
git submodule update --init --recursive

Flashing the UAVCAN Bootloader

Before updating firmware via UAVCAN, the ESC requires the UAVCAN bootloader to be flashed. The bootloader can be built as follows:

cd bootloader
make clean && make -j8
cd ..

The bootloader image is located at bootloader/firmware/bootloader.bin, and the OpenOCD configuration is located at openocd.cfg. Follow these instructions to install the bootloader on the ESC.

Compiling the Main Binary

cd firmware
make RELEASE=1 # RELEASE is optional; omit to build the debug version

Beware, some newer version of GCC lead to segfaults during linking. Version 4.9 did work at the time of writing. The firmware image will be located at firmware/build/io.px4.sapog-1.1-1.7.<xxxxxxxx>.application.bin, where <xxxxxxxx> is an arbitrary sequence of numbers and letters. There are two hardware version of the Zubax Orel 20 (1.0 and 1.1). Make sure you copy the binary to the correct folder in the subsequent description. The ESC firmware will check the hardware version and works on both products.1

Zubax GNSS

Please refer to the project page to learn how to build and flash the firmware. Zubax GNSS comes with a UAVCAN-capable bootloader, so its firmware can be updated in a uniform fashion via UAVCAN as described below.

Firmware Installation on the Autopilot

The UAVCAN node file names follow a naming convention which allows the Pixhawk to update all UAVCAN devices on the network, regardless of manufacturer. The firmware files generated in the steps above must therefore be copied to the correct locations on an SD card or the PX4 ROMFS in order for the devices to be updated.

The convention for firmware image names is:

<uavcan name>-<hw version major>.<hw version minor>-<sw version major>.<sw version minor>.<version hash>.bin

e.g. com.thiemar.s2740vc-v1-1.0-1.0.68e34de6.bin

However, due to space/performance constraints (names may not exceed 28 charates), the UAVCAN firmware updater requires those filenames to be split and stored in a directory structure like the following:

/fs/microsd/fw/<node name>/<hw version major>.<hw version minor>/<hw name>-<sw version major>.<sw version minor>.<git hash>.bin



The ROMFS-based updater follows that pattern, but prepends the file name with _ so you add the firmware in:

/etc/uavcan/fw/<device name>/<hw version major>.<hw version minor>/_<hw name>-<sw version major>.<sw version minor>.<git hash>.bin

Placing the binaries in the PX4 ROMFS

The resulting finale file locations are:

  • S2740VC ESC: ROMFS/px4fmu_common/uavcan/fw/com.thiemar.s2740vc-v1/1.0/_s2740vc-v1-1.0.<git hash>.bin
  • Pixhawk ESC 1.6: ROMFS/px4fmu_common/uavcan/fw/org.pixhawk.px4esc-v1/1.6/_px4esc-v1-1.6.<git hash>.bin
  • Pixhawk ESC 1.4: `ROMFS/px4fmu_common/uavcan/fw/org.pixhawk.sapog-v1/1.4/_sapog-v1-1.4..bin``
  • Zubax GNSS v1: ROMFS/px4fmu_common/uavcan/fw/com.zubax.gnss/1.0/gnss-1.0.<git has>.bin
  • Zubax GNSS v2: ROMFS/px4fmu_common/uavcan/fw/com.zubax.gnss/2.0/gnss-2.0.<git has>.bin

Note that the ROMFS/px4fmu_common directory will be mounted to /etc on Pixhawk.

Starting the Firmware Upgrade process

When using the PX4 Flight Stack, enable UAVCAN in the 'Power Config' section and reboot the system before attempting an UAVCAN firmware upgrade.

Alternatively UAVCAN firmware upgrading can be started manually on NSH via:

uavcan start
uavcan start fw

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