Mavlink to FrSky S.Port Passthru Converter for LRS or PX4 Pro

I am having some trouble setting up the mav2pt converter. I followed this guide to get telemetry on a horus X10S Express, but there is no telemetry shown. I simply uploaded the precompiled

Mav2PT_v2.46.ino.TEENSY31.hex

firmware to a Teensy 3.2, but it doesn´t work. How is the precompiled hex firmware configured? Any ideas what I could try next? The Teensy led does blink once every second.