Tried to digest pretty much everything I could find on the AT&T 640 firmware lockdown (here and on XDA) and I'm still 50/50 on whether this thing will ever be debranded. I honestly don't know.
As I understand it, the AT&T firmware is the latest "v8" firmware in existence (02177.00000.15184.36016). And given that pretty much every other carrier isn't selling the phone anymore, I don't how any of them will get an update to use as a baseline for the Phone SDK, to force an update off the AT&T firmware. Should be interesting however to see what happens if v10 FFU's are eventually released...will the only carrrier to get the "official" update be AT&T?
I actually considered a TMo version care of FleaBay, but the few that are out there are selling upwards of USD $125 now so I've pretty much given up on that (especially since the phone is effectively dead to Tmo). I suppose I can eat the $40 I paid for this BF deal and use it in its crippled form as it's still a decent phone for that price. And it was interesting crash-course on Windows Phone firmware tricks and tips, that's for sure.