It took a while to get it figured out and I don't remember everything I did, but it went something like this:
- Create a model in radio.
- On the Model Setup page, set the Internal RF Mode to ACCST D16 and Channel Range to CH1-8.
- Connect TH2 to Betaflight.
- On the Configuration tab, set Receiver Mode to SPI RX Support and SPI Bus Receiver Provider to FRSKY_X.
- On the CLI tab, type BIND_RX (or BIND_RX_SPI, depending on your version of Betaflight). The red LED on the TH2 should be flashing and the blue LED on solid at this time.
- Back on the radio, select Bind. It doesn't matter if you select Telemetry On or Off. The blue LED on the TH2 should start flashing.
- Type SAVE on the CLI tab in Betaflight.
- Check the channels on the Receiver tab in Betaflight to make sure it worked and everything is on the correct sticks.
Hopefully, that will work. Here is a video that seems to have the steps. I didn't use this exact video, but there was another that I found back when I was trying to bind them.
By the way, I'm using an FCC (US) radio with OPEN TX version 2.3.7 and Betaflight Firmware 4.1.0 (Configurator 10.7.0). Not sure if this works the same on an LBT (EU) radio.
Good luck.