I have an Xbox 360 which I bought in 2012 brand new, I used to save profiles and games to memory unit (this was before I even knew about hard drives for Xbox 360 or even flash drives) I have since formatted the memory unit with the format option. However I have recently heard that doesn't completely erase everything from the memory unit, I have heard there is an eraser specifically for the memory unit downloadable to run from a usb flash drive. Is this true?