Trouble w/ GPS on GalaxyS Vibrant, Froyo 2.2?

I recently upgraded my Samsung Vibrant to Android 2.2 through Kies. But now I'm having bad GPS problems. At the point where it doesn't work at all. If I have the GPS active and go to google maps for example, it freezes, and won't do anything. Then if I deactivate the GPS, the map app works like a champ. Which is somewhat useless, considering no GPS. I've tried getting into the settings from the old Android 2.1 GPS fix, using the dialer code *#*#1472365#*#* and tweaking some options.. but it doesn't seem to work the same on Froyo. Is there a new dialer code on 2.2, to get to those settings? Or is there a way to downgrade back to 2.1 or even reinstall the 2.2 update to see if that works? Any help would be appreciated. Have tried the GPS in other apps too, MyTracks, Navigation, and still broken.