My P3S gimbal is off the drone because of non-reparable issues. I do not plan to replace it as I would like to upgrade to a P3A. However, I would like to fly the P3S as is but I will not be using the GO app as it will not communicate with a drone sans gimbal. The controller will allow compass calibration and I assume RTH. I don't know about calibrating the IMU. I guess I cannot upgrade FW on the drone as well as change any parameters. Now comes the questions. How does RTH work, i.e., what are its parameters? The same goes with max distance and altitude. Will it just remember the last set of parameters just before the crash or is there a way to change parameters and upgrade FW, etc., using the USB port and a computer?