I've been using an ATT 8820 on T-mobile for months now, no problems. I noticed that T-mobile started selling the 8820 on Tuesday March 24. So I loaded their handheld OS, ver. 4.2.2.193. I have, what I believe to be, all the certificates installed for UMA, t-mobile_root, t-mobile_trustcert, us.tmobile.midp.SemiTrust, and us.tmobile.midp20.FullTrust. All are installed and have a green check mark. I only restored a minimum of apps, did a battery reset, reloaded service books, and thought UMA might work. Well, it doesn"t. I'm using WiFi at home WPA-Personal TKIP, and have no problems. Does anyone have any idea's as to what could be wrong? I would think that T-mobile, since they already know I have an 8820 from my pin number, would have turned on, in their service books or certificates, UMA for an 8820. They don't have one in their store yet, April 20th or so, so I have not been able to compare.

You will likely never get UMA on your unlocked AT&T 8820. Only a TMobile branded device will work. Same with the 8320. Other unlocked 8320's will not get UMA, either.

this is the unfortunate with t-mobile's UMA. It only works with branded t-mobile devices. Try to sell the at&t 8820 and get the t-mob 8820.

Good idea!

Thanks John and Dinan3 for the info. Looks like some, or all of the necessary UMA service books are hard coded in to the device, and I don't know of any way of changing that. Selling it, and picking up a T-mobile 8820 is the only way I'll get UMA.

I got an 8820 from T-Mobile 13 days ago. It seemed fine until yesterday or day before. Then it started dropping calls and sustaining a lame connection at best. T-Mobile tech support had me wipe the device, which left it in worse shape--now it won't even dial. At least I don't have my mother-in-law's phone number in my pocket for the moment. Is there a widespread problem with T-Mobile's 8820?

There are many issues that could cause this from a problem with your device, to a router issue to an ISP issue. What kind of router are you using? What ISP are you using?

^Any fix for this yet?