For those of you who want to install custom ROM on your rooted AT&T HTC One X or HTC One XL, here’s a fail-proof method by booting custom recovery from fastboot.
Drivers for Windows (if you need it):
Step 1. Copy the custom ROM zip file (do no unzip) to somewhere on your phone. Or you can also download ROM zip file straight to your phone, it should be under Download directory.
Step 2. Make sure USB debugging is checked ON under Settings->Developer options.
Step 3. Open a command prompt (or terminal in Mac/Linux) and type:
adb reboot bootloader
fastboot erase cache
fastboot boot openrecovery-twrp-2.1.7-evita.img (updated with TWRP 2.2)
fastboot boot openrecovery-twrp-2.2.0-evita.img
Step 4. Before you install a custom ROM, use the Backup feature to backup your ROM!
Step 5. Choose “Wipe” from main menu and choose “Factory Reset”.
Step 6. Choose “Install” from main menu and find the ROM zip file you copied over earlier.
Step 7. Once your ROM finishes installing, reboot and enjoy your new ROM!