Mavros communication with new navigator flight controller


I am trying to configure an image running MAVROS in the Raspberry Pi 4 (Ubuntu 20.04 / ros-noetic) to work with the new Bluerobotics Navigator Flight Controller but when I try to initialize MAVROS I am not receiving messages nor a heartbeat from the Navigator Controller. I am running the following one liner:

roslaunch mavros apm.launch gcs_url:=udp://@ fcu_url:=serial///dev/ttyAMA0?ids=255,1

This has worked before in our previous BlueROVs with a Pixhawk and RPi3 (Ubuntu 18/ros melodic). The only thing I am changing so far is the serial device because the Navigator Controller is not connected the same way as the Pixhawk.

What else should I change or look for?