So what happens when you put a T-mo sim in an unlocked ATT Bold? Does the phone just run on edge, or does the phone attempt to continuously connect to a 3g network?

3g not available.TMO 3g uses a different frequency. Go to options > Mobile Network > scroll to network mode and select 2g

No i understand that...not to mention you can't even shut off the 3g option on the ATT bold. What im asking is, if i have an unlocked att bold, and you can't shut 3g off, does the phone operate just as well as say as a rogers bold unlocked, or does the phone operate correctly since there is no 3g signal? Will it run off edge?

I have stated this many times. It is only locked with an AT&T SIM and an AT&T Bold. An unlocked AT&T Bold with another carrier SIM will allow a 2G selection.

Yes, it runs on Edge. My friend got an AT&T Bold yesterday, unlocked it, and uses it with his TMO SIM, no problems.

Thank you sir.

I think AT&T made a HUGE mistake with this lock!

If I put a Tmobile SIM in my unlocked ATT Bold, flip off the 3g, and then put the ATT sim in it, will it stay in 2g mode. I can't make it through a day in 3g without a recharge.

No. This thread is old, and does not contain correct information.

The lock on the mode selection is based on the Vendor ID of the device. Therefore, regardless of what SIM card is in a Bold with Vendor ID 102 (at&t), the option to change between 2G/3G/3G & 2G will not be present.

Please see this thread for further details:
ATT No Option for Edge Only Like on Rogers

Troy, I Agree 100%! That is why I purchased an unlocked Rogers Bold, and am using it on the AT&T network.

It's great to be able to assign the specific network you want to use. Being that I'm on the fringe of the 3G coverage (Living In The Woods), I can select EDGE or 3G specifically.

No more of my device always hunting for the stronger network to lock in on.

Matt