Today a friend got a new GPS and after a 1/2hr or so of use he found it would not update his location (but still has a gps fix thats been updated) we had tried doing a hard reset and that worked for a bit. He then went home and done a softwear update on it and still had no joy so after looking on tomtom help pages I found this, through I would post it here for the rest of you. Hope it helps some one.

Mandatory software update to restore GPS signal  for faulty not going Via 220, Via 160/180, Via 260/280, GO LIVE 820/825, GO 1000, GO 1050/1050 World and GO LIVE 1000/1050/2050/2050 World.