I have the same issues with my 7710. I sent it back once because the USB went bad and it would not hold a charge or update when synced to the computer. Sent it back and they sent me a new refurbished one. Took the time to load my entire 7500 mile trip on it to stat the summer, and 1500 miles in it went blank. Re-booted it and it worked for a day, then blank again. Re-booted it a second time and it froze and won't even re-boot now. POS IS CORRECT. was going to request a 7720 as we'll, so I am disheartened to see they won't upgrade for others. Basically a waste of money. Not to mention, it took me on MANY round about routes and a few dead-ends. Thankfully, I was able to see the dead end before I actually made the turn. Not impressed with the product at all.
2014 Berkshire 390BH-40
2012 Chevy Equinox - TOAD