Step by Step Instructions:

1. Download the following two files:
   1. HTC Sync software →  You’ll need it for installing proper drivers  for your phone
   2. Fastboot files → download link These are the files required to run fastboot commands on your Windows PC
2. Now install the HTC Sync software you downloaded in Step 1.1 on your PC
3. Extract the “fastboot.zip” file you downloaded in Step 1.2 on your PC, you’ll see a folder named “fastboot” with the following four files inside it:
   • adb.exe
   • AdbWinApi.dll
   • AdbWinUsbApi.dll
   • fastboot.exe
4. Now put your phone in bootloader mode:
   1. Switch OFF your phone.
   2. Press and hold “Volume down + Power button” together until your phone boots into bootloader mode.
5. Select Fastboot using the Power button. Use the Volume buttons to go up & down and Power button to select the highlighted option in the bootloader mode.
6. Connect your phone to the PC with a USB Cable.
7. Open the fastboot folder that you extracted in Step 3.
8. Then open a Command prompt window inside the fastboot folder. To do this → “Shift + Right Click” on any empty white space inside the folder and select the ‘Open command window here’
9. Type the following in the command prompt window: fastboot devices This is to ensure that your device is detected, if nothing appears on screen with this command, then it means you don’t have the proper drivers installed on your PC. And if that’s the case you should download and install/re-install the HTC Sync software given in Step 1.1
10. Now type the following command to re-lock your HTC One X bootloader fastboot oem lock
11. That’s all. Your phone’s bootloader is now re-locked and it’ll reboot automatically To confirm, boot into bootloader mode (follow Step 4.1 & 4.2) and you’ll see “RELOCKED” written with a pink highlight at the top of the screen