ok, so I just did the most recent update and re calibrated tx and compass. failsafe is set at RTH. According to nazza assist when the tx is turned off it goes into failsafe. just took a test flight, turned off tx mid flight and the phantom flys away. went back into assistant and changed my flight mode switch from manual to fail safe. now when i am flying and switch to failsafe with the switch the phantom does complete the RTH function. But once in failsafe I cannot regain control by switching the flight mode switch back to gps. I do regain control after I turn the tx off and back on again.
Also, when in normal flight and turning off the tx, it continues to fly away.