Even after SE’s explicit mention in their post that the process of unlocking the boot loader is not irreversible — if one unlocks the boot loader, he won’t be able to re-lock it — XDA member ‘Blagus’ has made it possible. Yeah, the genius has created a small (98 KB) magical file that needs to be flashed using “Flashtool” to re-lock the boot loader. Great!

So now all you (few) people who regret unlocking their boot loader can now re-lock it. After re-locking you’ll be able to use SEUS again to update and repair your phone’s firmware, but you won’t get the “Facebook Like button in Music app” to work as this hack doesn’t restores DRM.

Below is how to re-lock Xperia Arc boot loader:

Requirements:

  1. PC Companion and Update Service installed on your PC
  2. FlashTool_0.2.9.1.exe – Download link
  3. Xperia Relock bootloader.ftf – Download link

Short guide:

Download & extract ‘FlashTool_0.2.9.1.exe’ on your PC, put the ‘Xperia Relock bootloader.ftf’ file inside the ‘firmwares’ folder, and flash. That’s it.

Video Guide:

Step by Step Guide:

  1. Download the files given above in requirements.
  2. Double click on ‘FlashTool_0.2.9.1.exe’ file to extract it, Or you can use free software like ‘7 zip’ to extract it.
  3. Few files and folders will be extracted — the one which we’ll be using for flashing “Xperia Relock bootloader.ftf” files is the “firmwares” folder.
  4. So copy the “Xperia Relock bootloader.ftf” file that you downloaded above, and paste it inside the “firmwares” folder.
  5. Now double click on the “X10FlashTool.exe” file to run the program.
  6. Once the program opens — click on the “Flash” button.
  7. You’ll see a screen like the image given below — click “Ok”!Relock Xperia Bootloader
  8. Now it should ask you to connect your phone to the PC. So first plug the USB cable to PC, then pick up your phone and hold the “Back” key (key at the bottom left on your Arc), and then connect the USB cable to your phone. Remember you’ve to hold the “Back” key while connecting the USB cable to phone.
  9. Once the phone gets connected — Flashtool will automatically start the flashing process.
  10. Keep an eye on the Flashtool’s screen.
  11. And once the process gets finished, disconnect your phone from PC and switch it ON.

Enjoy!

All thanks to XDA member Blagus for making it possible to re-lock the boot loader. Head over to this thread on XDA to thank him for his awesome work.

https://nerdschalk.com/how-to-unlock-bootloader-xperia-arc-play-neo-pro/ [/info]