I would get your fin replaced asap. It ended up being the cause of the ACC constant error I got. Renewed it and it went.
As for software updates - I may or may not have done mine (cough) from an online source. Yes, I crapped myself about bricking a car, but it worked, and going over the new Forth Road Bridge doesn't show me in the middle of the Forth.
It take a bit of time, but if you follow the instructions to the letter you should be fine. You obviously do this at your own risk. Sadly, the loss of the Google Earth connection means I just use my phone for all navigation now. Plus Google maps is much more intuitive.
But get the fin sorted. You may still be under warranty for that if you bought it off a dealer. I was.