It took me several attempts. Initially I wasn't doing the lock unlock presses quick enough I think. The switch on in ACC mode, with drivers' door shut, followed by 10 presses must be done within 10 seconds.
Having successfully registered 2 Android phones on Monday, yesterday the app on one phone had to be updated. Then the vehicle software had to be updated. Repeatedly the updated app phone failed to connect to the vehicle but I was then able to connect the other phone which did connect, and, in registration mode as for pairing, the vehicle software update happened. It warns you that ACC must stay on and contact maintained for up to 10 minutes for this to happen.
Afterwards I still couldn't get the updated phone to connect so I'm going to work on that today.
Good luck.