Looks like the AT&T version of the HTC One X differs from the international version in more ways than just the processor found inside. Paul O’brien and friends over at MoDaCo have uncovered an interesting bit of news about the AT&T One X that could pose a problem for those looking to flash custom ROMs onto the device.
According to Mr. Obrien, he and a few others are being greeted by a “MID ERROR 160” when attempting to unlock the bootloader on the AT&T One X through HTCDev. Again, this error hasn’t showed up when unlocking the Euro or Canadian version of the One X and seems to be a unique issue only to the AT&T version. There’s a wide range of reasons why a carrier would want to go through the trouble of requesting a device’s bootloader remain locked and it’s also very possible that a future update could fix this roadblock. But as it stands today, the HTC One X on AT&T is currently un-unlockable.