Hi there. I am mounting the FrSky RXSR receiver to my Omnibus Fireworks V2 Flightcontroller. Can somebody tell me: Do I have to do the soldering hack on the receiver, or is there a setup I can do in the Betaflight Configurator, to get Sbus and Smart Port working with Lua Script? It seems like the Uart 1 and TX 1 are the same. It's the inverter problem that FrSky recivers have

RC pad is for sBus, built in inverter

As RENO said, for SBUS, just connect the SBUS pad from the R-XSR to the RC pad on the Omnibus. No inversion hack needed.

For SmartPort, you will need to do one of the following:-

1. Connect the S.Port pin from the connector on the R-XSR to the TX pad of a spare UART on the Omnibus and then map SoftSerial to that pad in the CLI so it will use software on the Omnibus to uninvert the signal. You will also need to enable SoftSerial in the Configuration tab and configure the UART for SmartPort in the Ports tab.
   
2. Solder a wire from the minuscule uninverted pad in the middle of the R-XSR board to the TX pad of a spare UART on the Omnibus, then configure the UART for SmartPort in the Ports tab.
   

Alternatively, just install F.Port firmware on the R-XSR receiver instead which means you then only need to connect a single wire that carries both SBUS and telemetry data. For this, you connect the SmartPort pin on the R-XSR to the RC pad on the Omnibus. The SBUS pin on the R-XSR remains unconnected. Then set the receiver protocol as FPort in the Configuration tab and also run the following commands in the CLI:-