No MAVLINK-telemetry with Mario AIO cam

[handbrems]

With Mario AIO cam there is no telemetry possible, neither on UART0 nor on UART2. I've tested with several baud rates. Settings:

• Telemetry MAVLINK
• any FC sys ID allowed
• refresh rate 4 Hz
• telemetry options read only
• request data stream no

Setup:
Ruby 9.4
Air unit
-Mario AIO cam
-Ardupilot MAVLINK
Ground control station

• radxa 3e
• 2x ASUS AC-56

Same setup runs with Pi zero 2 and AC-56 on a second vehicle and replies telemetry.

[Mauronic]

I am interested in using MAVLINK telemetry features for the exact hardware setup as @handbrems. I need to confirm my minimum refresh rate requirements, but I'm curious what the maximum rate this configuration will support.