Hi B-Bird:

How did you update the 4649T? I see the fw update software tool is available but didn't see where the 1.9.9 fw file is?

You seem to have this figured out. Can you share?

I updated all components to the latest SW: 4649T (1.1.9), Spirit (2.4.4), DX9 (1.21) and used the second input of the receiver as mentioned above by treys1.
-> everything is working now, i have ESC-telemetry in "ESC", BEC Voltage is shown and i can set an alarm and "Capacity used" is shown in correct menu (Alarming should be possible here as well). Thank you very much - i think this is the best solution with lowest effort in all of my setups