I have a Phantom 1 and I have fast double yellow (atti) or green (gps) all the time - when stationary with motors stopped and while flying. Manual talks about tx sticks needing calibration, but I have done this stand alone and with assistant and it shows the sticks are correctly centred. I've done imu calibration and compass calibration. She flies fine, so not sure if it's something to worry about or not? The manual also says: After powering on and before the motors start, if the aircraft LED double blinks yellow or green without Transmitter stick movement, you should power cycle the aircraft. Any ideas?