As with a computer, a GPS Tech might be able to salvage information even though current GPS will not work. It does have a memory and a tech might be able to help. Maybe you have already tried this, but if not it might be worth a call. The with the manufacturing company, also.

TOM (snookman47)
www.TheFishermansCatch.com (We sell Fishing Books, Tackle, Clothing, Guides Books, Fishing Magazines, Accessories)