When HTC confirmed to us that it wouldn't be offering an official bootloader unlock solution for the AT&T version of the One X, we assumed that the Android hacking community would step in and find a solution. Twenty days later, that solution is here via a process detailed by grankin01 at xda-developers. The process involves using the command line and a hex editor to trick HTC's tools into believing that the AT&T One X is a Canadian version, thereby allowing the bootloader to be unlocked. Be forewarned that as of right now there isn't a simple script for this process, but instead a twelve-step program during which a typo could brick your device. It probably won't be too long until a simpler and safer solution emerges, but if you absolutely can't wait to hack away on your AT&T One X, the door has been opened.
AT&T HTC One X bootloader unlocked via command line trickery
AT&T HTC One X bootloader unlocked via command line trickery/
Android developers have unlocked the bootloader on the AT&T version of the AT&T One X.