hello,
try to patch the navcore:
How to patch the ttsystem or pndnavigator for PNA
and then activate the map you want:
How to activate the maps for TomTom
You have to do both things to get the gps running again
If you do this you will have a "cracked" gps and in the future you just need to download new maps and activate them
Good luck
MAKE A BACKUP FIRST!!