This file removes the key, therefore relocks the bootloader.
Flash with FlashTool.
You still can't get DRM back. It's gone from the phone!
Feel free to donate if this helped you
If you unlocked your phone with SEtool/Omnius - any testpoint unlock solution - YOU CAN NOT RELOCK BOOTLOADER! IT'S PATCHED SO IT APPEARS LOCKED TO SE, BUT ACCEPTS UNSIGNED IMAGES VIA FASTBOOT! SO STOP ASKING ABOUT IT, AND STOP TRYING.