HTC One X Android devices bought through AT&T are locked down devices, but no worries as talented developers from XDA forums have cracked the HTC One X bootloader to unlock the phone. This method is unofficial and not authorized, though they used HTC Dev tool to unlock the phone.
If you want to unlock your AT&T HTC One X, follow the procedure listed below.
Keep in mind this will erase everything on your device. Backup everything before proceeding and do it at your own risk. If you have never done this kind of stuff then stay away.
You need ADB and an understanding of how to use it and have a rooted device (although I didn’t test this). You will also need a hex editor like HxD.
BACK UP YOUR DATA BEFORE DOING THIS!!!! WHEN HTCDEV UNLOCKS YOUR DEVICE YOU MUST START FROM SCRATCH!!!
1. Fire up your command prompt and go to the directory that you have ADB installed to. Type “adb shell” and hit enter.
2. Type “su” and hit enter. You now have root privileges.
3. Next type “dd if=/dev/block/mmcblk0p4 of=/sdcard/mmcblk0p4” and hit enter. This will dump the partition to your sdcard.
4. Next type “exit”, hit enter, type “exit”, and hit enter again. This should take you back to a command prompt for your computer.
5. type “adb pull /sdcard/mmcblk0p4” and hit enter. NOTE THE SIZE OF THE FILE BEFORE THE NEXT STEP!
6. Open the file (mmcblk0p4) with your hex editor.
7. Look for offset 00000210 (if your on RUU version 1.82 the offset may be 00000214) and you should see CWS__001 with your IMEI number attached to it.
8. Change CWS__001 to 11111111 and save the file as mmcblk0p4MOD. This will give you SuperCID as well. MAKE SURE AT THIS POINT THAT THE FILE IS THE EXACT SIZE IT WAS BEFORE YOU HEX EDITED IT!
9. Now go back to your command prompt and type “adb push mmcblk0p4MOD /sdcard/mmcblk0p4MOD” and hit enter.
10. Type “adb shell” and hit enter then type “su” and hit enter again. This will put you back into the android shell and give you root privileges.
11. Type “dd if=/sdcard/mmcblk0p4MOD of=/dev/block/mmcblk0p4” and hit enter. To test if it worked restart the phone into fastboot (type “adb reboot bootloader” and hit enter) and once the bootloader screen comes up type “fastboot oem readcid” and hit enter. It should read “11111111”.
12. Next type “fastboot oem get_identifier_token” and hit enter. Leave that up on your screen and go to HTCdev.com. Follow the instructions from there. Choose “All other supported models” from the dropdown menu.