I'm using a UBlox M7 GPS unit, with external mag to provide some GPS flight modes to my OP Revo.
When I plug the main battery into the FC, the ESC's beep, but the board won't arm. When I plug the board into USB I find that the flex and main port settings seem to have reverted to 'Disabled', which obviously stops the board arming because the GPS Flight modes result in a config error.
After some fiddling about (generally involving setting Flexi to I2C and Main Port to GPS, then power cycling twice), I can get the board to boot with both ports enabled, and everything works fine and I can fly. However when I change the battery, I have the same issue - the board will have forgotten the port settings again.
I am using next firmware and Librepilot in order to use the external mag through I2C. I appreciate this is a development release, but I haven't seen anyone else reporting this issue, so thought I would ask.
Any ideas? Please let me know if you need any more info.