I just had a scare while updating my Garmin Marine Network. You just plug in a memory card with the updates and turn on the network and everything updates with only a button or two to push. Or at least thats how its supposed to go. My GDL30A marine weather 'black box' froze the update process. After waiting for about an hour (half that time on hold to Garmin) a tech talks me through a few steps which didn't work. He seemed to know little about my setup (3000 series head units). He told me if the unit died, there is no weather box compatable with the 3210 and I'd have to upgrade my plotters. Yea, like I want to spend that money right now. After he gave up with the help, I tried one thing on my own. I turned the battery switches off so all 12V DC to the boat was off. I let everything set for five minutes and then tried the update again and low and behold it worked! Apparently it needed a hard boot to purge the cache and allow it to do the update. I was unimpressed with the tech help from Garmin. I will also not update that unit again unless there is a problem.
So long story short, try turning off your batteries for a few minutes and see if it works after 'rebooting'.
Good luck.
