I have updated my 520 to this:
[TomTomGo]
DeviceName=TomTom GO 520
DeviceVersionHW=GO 520
BootLoaderVersion=55259
ApplicationVersionVersionNumber=9026
ApplicationVersion=483454.1
CurrentMap=United_Kingdom_and_Republic_of_Ireland
CurrentMapVersion=850.2821
all seems to work ok navigation wise, havent road tested it yet.
Quesion is - what about data ? I've paired it with two phones using bluetooth, handsfree calling works but I cant download data, no map correctiosn, no traffic get "Cannot connect to tom tom LIVE services try again later"
Am I being too ambitios here ? ;-)