I've been using the 3DR radios successfully on my ArduCopter for about 2 months now. I recently ported the radio and my APM to a newly built Skywalker 168cm with the hopes of an AP/FPV enabled fixed-wing aircraft.
After I uploaded the most recent ArduPlane software (2.5), I am having trouble reading telemetry from the APM on the MP. Radios are tested working outside of the APM environment (connecting to each other fine, sending serial data, solid green LEDs, etc.), however, under normal circumstances, when I power the APM and thus the connected aircraft radio, it immediately displays both a blinking red and green LED and fails to connect to MP (timeout error). APM connects to MP fine through USB.
(I am not attempting connecting with radios while USB is connected)
Has anyone run into this before? Perhaps I am overlooking something simple.