Hey I just got the OS update v4.5 on my BB curve 8310.
I then tried to refresh my GPS and it came up with nothing! I had it working on the earlier version. Why not now?
The OS upgrade typically wipes out everything. To get the GPS going, make sure that you have "Location Services" set as "ON". The go outside, with a clear view of the sky and let it find the satellites and lock on. Might take 20 minutes or so.
To speed things up, and assuming that you have a BB data plan, install Google Maps and let it locate you as close as possible using tower data and triangulation.