So I performed a map update yesterday, upgrading to North_America_865_3245. Everything "seemed" to work fine however when I pulled my GPS out of the cradle it would not power on. Looked like it would going to the colourful street screen but would then shut down. Yet it would function fine in the cradle. OK, so it's a battery issue.
NOT. I restored my original backup and it works just fine out of the cradle. So ...