A few weeks ago HTC confirmed that they would not release any sources to allow AT&T’s version of the HTC One X bootloader to be unlocked, well people over at XDA weren’t satisfied and now they’ve unlocked it. It seems as though user grankin01 has found an exploit by using some of the information from the Rogers version of the One X, after all Rogers and AT&T run off the same mobile spectrum so their device versions tend to be very similar. gankin01 has shared his exploit method and can be followed all in just twelve steps (found in the second source link). There are a few things to keep in mind though; attempting to unlock the bootloader could permanently damage your device, and in his instructions he expects you to have some small knowledge on how to use the ADB, don’t know how to get it up and running? I’ve got you covered as I explain how in this easy video tutorial. Do you plan to mod your device?
Source: XDA-Developers, XDAForums