I did this with a nano sim adapter. Well it worked at first. Then I went to switch back and noticed the nano sim fell out and the adapter was firmly in there. So I closed the sim tray and then couldn't reopen it. Took it to AT&T and the guy somehow opened it. But he said sim adapters are not supported. While there I tried the nano sim in the adapter. Now I get invalid sim. But nano sim works in iPhone. I showed the guy but he said I used it in an unapproved way. I think my sim slot is screwed up.