Hi all. It's been about a year since I last used my Phantom Vision 2. When I try to start it, I get only 2 flashing LEDs (back). The front LEDs are dark (no lights at all). Motor is not responding. And I cannot calibrate the GPS (do the DJI dance). The device is stock. No mods or upgrades of either software or firmware. I have crashed it a couple of times, though. But it flew fine after that, and fine when last using it. Any clues?