Hi All, I've been using 2 Nexus 7s for controlling drone flights for a couple of years. just encountered a problem using Litchi and was advised to upgrade to Android 5.0. from 4.4.4......Bad move, the Nexus barely moves and certainly will not run Litchi. Can anyone instruct me on how to reinstall 4.4.4 so I can start again? All help gratefully received>