Just received a new Zumo 550 last Tuesday prior to leaving on a trip to LA on Thursday. I successfully set it up on my motorcycle tested it and left for my trip and it worked fine to LA and hand held one day in LA. On Saturday heading home when I attached it to the mc cradle it did not power up, pushed the power button still did not power up. Took it out of the cradle and reset it, in case it did not seat properly, still did not power up. Took it out of the cradle and pushed the power button to attempt running it off the battery, still did not work. I checked the fuse, o.k., put it back in the cradle and left for my return home. At my first gas stop I tried same steps again to see if anything changed, still nothing, so I packed it away for the remainder of the trip. When I got home Saturday afternoon, I plugged it into the AC power, still nothing and also no charging message. Then on Sunday tried all the above steps again, still nothing. This morning, convinced the unit was dead, I called the vendor to arrange a return and replacement. Just before packing it up, for kicks and giggles, I gave it one more try and voila! It decided to work. Since it seems to be working I'll hold off sending it back and try to heavily use it to see if I can get it to fail again. In the meantime I have checked firmware updates and although the message indicates my unit is up to date, I ran the update again. What gives any thoughts?