I was attempting to verify/upgrade the remote controller firmware using the RC Assistant software. According to the user manual, to access the Micro USB port for the remote controller you must "open the rear cover to find the Micro-USB port on the board inner the remote controller". I was able to remove the 4 screws holding the back cover on but at that point it becomes clear that there is also a collar near the base of the antenna that must be removed. Can anybody please provide instructions on how to safely remove this collar and access the USB port inside the controller?