If your transponder is Mode C, none of this will work.

1. The transponder, if Mode S, has to be configured to your ICAO code. Note that this is a specific process for your particular transponder that is set out in your transponder installation manual by the transponder manufacturer.

2. the PowerFLARM configuration file has to have the same ICAO code.

From Configuration tool:

" empty to use the device specific radio id..."