On my experience, with other devices (drones), that have the possibility of update the firmware via mobile, is not useful. I don´t know why, but always I have problems or misfunction after the update via mobile and when I update with a cable to the computer these problems not appear. Is not only my problem, a lot of users have the same problem and recommend use the computer to update. Safest way, plugged to the energy and more fast solution. Normally a update via mobile need around 30-40 minutes to be completed, and only 10-15 by cable to computer. Maybe with nice coding this can be avoided, I don´t know.