I had the very same problem with an r9mm and a kakutef7 and managed to get it to work by swapping rx/tx and enabling built in pullups An Open Source Frsky Telemetry Script for the Horus X10,X12 and Taranis X9D,X9E and QX7 radios
I had the very same problem with an r9mm and a kakutef7 and managed to get it to work by swapping rx/tx and enabling built in pullups An Open Source Frsky Telemetry Script for the Horus X10,X12 and Taranis X9D,X9E and QX7 radios