Had the same issue just now. Not only I had to re-try downloading and transferring the firmware maybe 10 times, I then couldn’t enter the maintenance mode until I googled it. Turns out, I had to press and hold the button until the full circle lid up, then press next and then keep holding it until only the top part turned on. Very frustrating, why does it have to be so difficult?
Also, I think the lock should be automatically updated through the Bridge, with just one press of a button. Why not?