This is a collection of tips and tricks to solve issues when setting up or working with the UAVCAN.
If the PX4 Firmware arms but the motors do not start to rotate, check the parameter UAVCAN_ENABLE. It should be set to 3 in order to use the ESCs connected via UAVCAN as output. Moreover, if the motors do not start spinning before thrust is increased, check UAVCAN_ESC_IDLT and set it to one.
A great tool to debug the transmission on the UAVCAN bus is the Zubax Babel in combination with the GUI tool. They can also be used independently from Pixhawk hardware in order to test a node or manually control UAVCAN enabled ESCs.
PX4 requires an SD card for UAVCAN node allocation and firmware upgrade (both of which happen during boot). Check that there is a (working) SD card present and reboot.