Hi Max,
In the AQ GCS I installed the LadyBird V2 config file, transmitted and wrote to M4. I checked the radio settings, and RC1 is set for the internal CYRF receiver. I'm not using an external receiver, so RC2 is set to No Radio. I even tried to switch between RC1 No Radio and RC2 CYRF, with no difference. It's hard to see in the video, but the yellow debug light is blinking rapidly.
Sorry I meant Can Bus connector, not Sbus.
Video of M4v2 - Start up test - https://youtu.be/byN1MQ4C5Zk
Erik