I have had an AT&T HOX since about a month after it's been released. It's S-OFF, rooted, running CM 10.1, etc.
Now that T-Mobile is paying ETFs I'd like to get it unlocked and switch carriers. The problem is that if I cancel service from AT&T it'll still take a few days for them to give me the unlock code, and they've refused to give me an unlock code before I cancel my plan. As far as I can tell there's also no way to pay the early termination fee without canceling service.
So, is there a simple way to get the unlock code for free without going through AT&T? I heard that such an exploit exists for the One S. I'm willing to do a little terminal work.
Alternatively, which of the paid services is the cheapest and most reliable?
Also, I've heard that I'll need to go back to Sense to actually get the phone SIM unlocked. That's annoying if true, but not insurmountable.