HTC One X will need to have an unlocked bootloader and S-Off for this root method to work, and you should be able to do that at HTCdev.com using company’s official bootloader unlock tool.
Grab the root image download and instructions at android.modaco.
For those of you, who don’t remember HTC One X. it was announced at recently concluded Mobile World Congress and features Tegra 3 quad core processor, Android 4.0, and 4.7 inch 720p display.
