Restarts or reboots are often caused by a corrupted mapsettings.cfg file found in the map folder. Try removing it temporarily and reboot your device. It may fix the problem.
Also, try a hard reset by either inserting a paperclip in the reset hole, or by holding down the power button for more than 15 seconds.
Finally, the full featured UK map is actually 910_4892. This will give you more features than the 4952 map. Download it from here: