Hello, my 850T doesn't works as it should be since the last update. It only works for 10 min and doesn't clean anything. Before that he was cleaning during 1hour non stop, doing the tour of the appartement. I'm pretty sure it's due to the latest version of the firmware. Is it possible to go back to an older version of the firmware and make it works again ? I'm not able to use it right now, he became useless