Hey folks... having just gone around the houses to find this out, including a full factory reset of the phone, but it looks like the latest Google Maps upgrade to 4.1.1 breaks the GPS on the HTC Desire on T-Mobile. Not sure what others it might affect, but I have seen several reports of this around the net...
The symptoms are that the GPS only seems to see a few satellites, doesn't lock onto them properly and if it locks, it takes an absolute age... I was playing with it yesterday and I did manage to get a lock. Unfortunately it told me I was at 30000ft over the North Sea doing 125mph, when I was in fact walking along an old railway cutting not far from my house!
I spoke to T-Mobile, who were pretty much useless and they ended up giving me the HTC phone number and they suggested resetting the whole phone.
Then, after installing everything one by one with the GPS still working and the one that stopped it working was the Google Maps update. Uninstalling it fixed it...
