The latest OTA update to the HTC One X on AT&T broke root methods that used to work in the past. Not to be outdone by a simple update, members over at XDA Forums already have another root method for the latest 2.20 firmware version. This method will use two different exploits to modify your CID and allow you to unlock your bootloader and root the device.
As is the case with these sorts of things, the usual set of disclaimers apply. Use these tools at your own risk, and rooting your device can have some seriously negative consequences if you're not careful. That being said, we know many of you want to still take a look at this and get your devices rooted. Take a look at the source link below!
Source: XDA; Thanks, Trevor!