UMTS is 3G only. GSM is available everywhere, but UMTS is still being rolled out so you may not have full coverage on that setting (depending on where you live.) Auto will use UMTS when available, and otherwise fall back to GSM.
Some have speculated that it's the auto-toggling between the two bands that causes the radio lockup. Since you have tried locking it to GSM with no better result, I would say that's probably not the issue.
Looks like your on the AT&T 2.25 version. I'll PM you links to the Unbranded 2.27 version if you want to give it a try. |