Hi Vasily, >> maybe just the read sync train params command is broken? Can you change the init code and not send it and see if the rest of the init phase proceeds. I would rather have the secure connections actually tested before dismissing it altogether. > > I don't think that I have any devices that support secure connections > to test, I've got only a bluetooth mouse and headphones, both are from > the 2.0 era. > > FWIW unofficial recommendation from Realtek to Pine64 was to avoid > using any 4.1+ features on this chip. Unfortunately I don't have any > contacts with Realtek, so I can't confirm that. > >> Mind you, there were broken Broadcom implementation of connectionless slave broadcast as well. Maybe this is similar. > > I'd prefer to stick to what works unless there's some comprehensive > test that can figure out what's broken. check if removing the read sync trains params command makes the controller initialize and usable. Then we see about the rest. Regards Marcel