Aucune idée... par contre dans la doc il en parlent...  Unlock & power select mode (FOR HAM USERS ONLY!) Press button for 20 to 25 seconds. The Red LED will flash 3 times to confirm. You have unlocked the video transmitter for use with all frequencies (see frequency table below). NOTE: Unlock only works if you are inside the band selection menu     Plus précisément?   https://brushlesswhoop.com/betaflight-vtx-tables/