Hi, i too have a att device but for me it doesn't work, I tried with ARHD 93. I have bootloader unlocked, i am still S-ON. Did you need to install any tmobile firmware? Are you S-OFF?I installed the maximum rom on my att device, since it is an international rom, first I had to install the newest T-Mobile radios, afterwards it worked like a charm. It's great because I have very bad reception where I live. Now I have a global phone that runs T-Mobile wifi calling. Now on to mms and sms.