I bought for my wife ( 2gb 16gb gold). She has MTS CDMA & reliance GSM sim.
1st i put mts sim in sim slot 1 and it works. Thoghh i didn't check data mode on it. I put 2nd reliance GSM sim and it also works but after reboot the phone MTS sim had no signals. Again i rebooted phone and both works fine.
I still don't check data mode on MTS sim.