If your 520 can hold a straight line in flight the firmware is not going to be a problem. If you have the E-50 camera the 520 can stand off far enough to provide an ample margin of safety and still collect detailed imagery. An E-90 would need to be much closer. Either way, we started doing inspections before waypoint flying became a “necessity”, with the results being established by the operator’s level of flight skills. If you can fly smooth and steady, with a lens that provides good detail, there’s not a lot of cause to sweat the firmware.