Please help : APM activating telemetry port2

Hello all,

I have a APM2.5
I want to activate the telemetry port2 to output frsky telemetry.
I’d to first try on ardurover, then I will move to arduplane.
I have understood from the documentation, that the port 2 is only activated on the Pixhaw, probably for performance issues.
Please tell me which files I need to update to force it.
If there are performance issues, I can deactivate some features I don’t use.

Thank you

Benoit