Originally Posted by riprowan
Sent from my Nexus 5 using Tapatalk
Did you ever find an answer for this? I'm wondering the same thing myself. I have an AT&T HTC One (stock, never rooted, and under AT&T contract) that I'll be attempting to use via roaming in Italy soon. I'll let you know what kind of luck I have.
AT&T has told me that the phone should work fine (which I assumed), but they said the same thing with my old HTC OneX when I went to Morocco and Portugal last year and it never worked. FWIW, my GFs SGS3 (on same account as my phone) worked fine. We had ensured that identical options were set by AT&T CSRs to enable international dialing, etc, and the SGS3 and HOX both contained the same radios, so not sure what the problem was. I guess I'll see if it's fixed on the One soon enough.