I bought one of the Kindle Fire 7'' six-packs; my Kindles are a mix of Fire OS 5.0.1 and 5.1.1. But, the app I'm using to collect data for my research doesn't work with Android or Fire OS 5. I need to install Android 2, 3, or 4.
I found a way to root my devices (RootJunky's SuperTool). I'm...