Had the exact same thing, would just boot to a black screen with brightness around the edges looking like it was trying to start something but stalled. Turn the phone completely off, remove the battery, the phone chip and memory card, both should be under the battery and put only the back covering on. Place the charger into the slot and after 30 seconds or so, you'll see a robot with a progress bar above it telling you it's updating, let it complete. Then it will restart and update Android applications, let that finish, at the end it should boot into a simple interface, power it off. Put your chip, memory card and battery back in, and everything should be the way you had it, all configurations were the way I had left it before the update that I was constantly avoiding.