Most software updates you can do yourself go to the official website download the latest firmware version install it onto a SD card and plug it into the unit and it will generally take care of itself. Ive never done it on Furuno kit specifically but thats how it works on Garmin and lowrance finders.
There's not much to "service" with the kit. Radar units occasionally need to have the rubber band that spins the array replaced otherwise there's not much you can do there.