You don't even need to change the Flight Controller if you don't want to, I bought the micro OSD board mentioned here:
https://www.rcgroups.com/forums/showthread.php?2882184-Emax-babyhawk-OSD and meant to do this modification, but I didn't get the chance to before someone flying nearby with a more powerful VTX powered on and flattened my video signal, causing my gremlin to go down in a large area of dense overgrowth, where I presume the battery got ejected because I never heard the beeper.
No more wimpy 25mW VTXs for me. Ever. I tried to be a good HAM and run the smallest amount of TX power I could get away with, but after losing quads to video signal loss and careless interference from other FPV users, it's going to be full power all the time from here on out.