FrSky D4R-II upgrade to D16 protocol

Courtesy of Mike Blandford, of course!

FrSky D16 firmware for D8 receivers - RC Groups
RC Groups - View Single Post - FrSky D16 firmware for D8 receivers

And from Midilic...

FrSky D4R-ii – components, layout, and pinout – fishpepper.de

RC Groups - View Single Post - DIY FrSky TX/RX Modules