I can confirm FCC works great here, at Spain (europe), flying 1.0.3 firmware and 1.0.6 DJI Fly app version. For me, FCC hack doubles my range from 500 to 1000 meters at urban environment.
I followed all the detailed steps as read into this thread, but faced a problem when exit DJI Fly before landing in order to preserve hack. I realized that forced exit from app causes flight log corruption. Flight path ends abruptly in mid-flight, end half of flight path is missing. Looking for alternatives I succeed landing drone in a normal way (using DJI Fly app) but turnin off Mavic Mini as soon as it touches down, before it can process the changing WIFI region command from controller.
Best regards.
R.