Hi,
MigaoMiner: I had exact same problem, because my board is just missing chip for sd card. With this method you dont need boot from sd card. Just keep jumper in default position, connect uart bridge, disable ssh as described and then you can install another firmware like braiin os.

Jacoob007: as far as I know this is not possible at the moment. We can just hope that bitmain will change their minds and in next fw we will have option to enable ssh ...

Thanks and regards,
MK