HTC One X (htc-endeavoru)

Contributors

 * Clamor

How to enter HBOOT
+

From here you can navigate to recovery or fastboot mode.

TWRP
Flashing TWRP requires an unlocked bootloader, which has to be requested from HTC, see here.

The latest TWRP version contains a regression, an older version (3.1.1) is known to work. Download here. Bug is reported, any progress can be followed here