have kenwood DNX5260BT - lovely device.
I have updated maps and speedcams for Ireland & UK to the latest 2013.
After that sat nav navigation - somethimes is working ok , somethimes going to radio mode only. When i press NAV button - blank screen.
I have updated software to the latest 2.50 as well. Works again but after when i turn off my car and then come back after 10-20 mins - sat nav is not working again..
Did you load maps on to an sd card? Try turning on your unit > then remove sd card > let unit boot and see if navigation with old maps work > reinsert sd card and see if new maps load. Chances are you have an sd card that the kenwood unit does not find to it's liking. Best to use a 4GB non HS card. I am using an 8GB class 10 Samsung card at the moment in my 9960 and all seems stable. Kenwood units are very picky with what card you use. Many times the official Garmin map update sd card does not even load properly.
Another issue could be the speedcam file. I have recently encountered issues myself as the headunit going to blackscreen. Right before it does I see something about speedcam on display but it flashes so fast. The the Garmin software seems to reboot in a loop till I am a little further down the road. The reason I am here today is to get an updated speedcam file to see if this fixes my issue.
Seems very possible that speedcam file may be the culprit. Have read that cyclops does not work with kenwood units.