Ender-3-Neo NO BOOTLOADER at a V4.2.2 main-board

I have problem flashing a new firmware at my Ender-3-Neo. I follow all the directions given at this YouTube video (https://www.youtube.com/watch?v=UsAnYOonihM), but I cannot flash neither the new version of the firmware (, 2023-02-17), nor another firmware compatible with the V4.2.2 main-board. I contacted Creality Support, but they just resent me the same YouTube link I sent them… It looks like the bootloader does not exist in this V4.2.2 main-board, even if it should.

Does anyone had the same problem? If yes, how to solve it?