"You should have connecred Rx from radio to Tx on EB and vice versa.
If you're upgrading ground module's firmware - you have also to connect air module to PC and upgrade it's firmware to the same version. And also check if both modules have the same…"

"Try to swap two black wires next to red one.
But first check baudrate."

"Try to swap Rx-Tx lines, check baudrate (57k)."

"Rob, first check uCenter with direct connection to GPS unit, if this will sufficient for you. Than you can use radio link to connect this unit remotely."

"I've tested it before, both with NMEA and proprietary uBlox binary protocol - all works fine if you'll set correct baud for radio link.
But the question was asked over a half year ago and I'm not sure if is still valid..."

"Simple but worth considering :-)
PS. Pls, "Martin", not "Marvin" ;-)"

"He can connect i.e. M8N GPS receiver via radio link to PC running uCenter and control position from ground."

"Well, EN website version highly recommended..."

"1. This category is for 3DR Radio (telemetry), not for Pixhawk.2. There's no "geniune" or "fake" PIXHAWK - it's open hardware: https://pixhawk.org/"

"http://diydrones.com/forum/topics/hoperf-trp-project-targeting-marc..."

"That was discussed here a few months ago."

"You can always upload different FW.
But - If you're going to use bare HM-TRP - you have to pre-program bootloader first."

"Upload to HM-TRP and try."

"Those days I was playing Fedora with success"

"I'm sorry, I have no acces to this infrastructure anymore. Try to set up Linux environment using setup which was available around 2012...I remember that this was difficult to resolve dependencies even that time..."