I just purchased my DJI Phantom 2 a few days ago and on the initial test flight the indicator lights on the helicopter were blinking green as if it were synced with the remote control. On that first flight I turned off the remote and the P2 came back to where I launched it from like it's supposed to do. Ever since that first flight I can only get yellow blinking lights which means flight/wo gps. Everything else seems to be working okay. I can fly the drone and I've even done the compass calibration without a problem. Only thing it won't do now is fly with gps. Any suggestions on what my problem may be? I'm pretty new at this so any info will be useful. Thanks in advance.