[GUIDE] How To Re-lock Boot loader on Xperia Arc


Xperia Arc Boot Loader Re-lock Proof

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:


  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.


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.

[info] If you wish to unlock the boot loader again, then the process is similar to what you did the first time. If you help — below is a link to step by step boot loader unlocking guide:

http://www.theandroidsoul.com/how-to-unlock-bootloader-xperia-arc-play-neo-pro/ [/info]

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  • BOND

    How to unlock again??? And after relocking will bravia engine work correctly???

  • Hasan Adnan

    :D How smooth it was.. I just wonder..!!!!!!!!!!.Some p
    eople are really genius !!! ( Xperia ray st18i)

  • Matt

    Successful for Xperia mini ST15a. Thank you very mush!

  • Suraj

    Successful for Xperia Ray St18i happily running 4.0.4 with this process after using 2 Unofficial Rom’s :p ;)
    buy the way can i again unlock the Bootloader ??? ;) plz reply

    • http://www.theandroidsoul.com Shivam

      Yep. No probs in unlocking the bootloader again.

  • ilu

    swthrt love u

  • ANdroidNEWbie

    hi.. If i’m using custom rom can i relock it back without changing the rom?? i’m now using real ics 5 custom rom. cause i’m afraid if i relock it with custom rom which it needed custom kernel to avoid soft brick will be hardbrick. So my point is can i just relock it back with custom rom??

  • ANdroidNEWbie

    hi.. If i’m using custom rom can i relock it back without changing the rom?? i’m now using real ics 5 custom rom. cause i’m afraid if i relock it with custom rom which it needed custom kernel to avoid soft brick will be hardbrick. So my point is can i just relock it back with custom rom??

  • http://www.facebook.com/hugo.boss.1990 Hugo Boss

    i can’t download

  • Ed

    it not just only works, but also simple, thanks so much

  • reggie

    Oh my God THANKSSSSSSSSSS YOU VERY MUCH, I test on Xperia Active ST17i and it works excellent, thank you thank u

  • tilu

    need information regarding live with walkman relock http://relockbootlockerwt19i.blogspot.com/

  • http://www.facebook.com/profile.php?id=100001130473178 Raffy Manalaysay

    i am using the official ICS 4.0.4 for xperia arc and its rooted, if i relock my bootloader, will it remove my root access?

  • Braanbueno

    Gracias! ThankU perfect in my xperia RAY

  • http://www.facebook.com/profile.php?id=100001594299545 Суммасщедшый Любовь

    yoooooooooooou are aweeeesome man
    i love you
    it works on my Xperia Arc S
    now i’m able to update it to the Android 4.0

  • Yogesh Middha

    where’s TEST folder? plzz provide link

  • Himanshu124

    i m using builduser@buildhost#1 kernel and a AOSP ICS beta Rom. will this method work for me? or will i have to first install a stock rom and kernel?

  • AJ Saints

    how would i know if my arc’s boot loader was successfully re-locked?

    • HelpingGuy

      Just go to phone, then dial *#*#7378423#*#*. after dialing go to service info –> configuration… THEN VUELA! THERE YOU gO!

  • http://www.facebook.com/pdrito.rosado Pedro Rosado

    link don’t work

  • http://www.facebook.com/profile.php?id=100000619242672 Usman Ilyas

    Can i relock my xperia ray by this procedure?

  • Hh

    not working… tried 10s, but nothing,can’t update via update service or pcc

  • Enrico

    Where is the folder ”TEST” ?

  • Thankful

    Please update. After step #10. The Flashtool tells you to enable USB Debugging and also “unknown sources”. It DOESNT tell you after this step to PLUG IT BACK IN straight away and therefore does not complete properly. Cost me about 3 hours… :-

    Anyway, all good now, updated back from CM7.2 to STOCK SE 4.0.2.A.0.42 (living in Australia)

    Thank you very much for the guide!! Loving the stock again ;-)

  • hamad

    could you please tell me where the folder “test” is? please i reached the final step and im stuck here

  • Serdar

    after this process can I update my pda via se pc companion?

    • http://www.theandroidsoul.com Shivam

      Yeah you can :)

      • Serdar

        thanks m8 : )

      • Serdar

        hi again…
        m8, I have installed flash tool and downloaded the firmware which is highligted on above (Xperia_Relock_bootloader) and put it in to firmwares folder. however when I start the flashtool and hit to flash button in the program, I can not see the loader.sin at the firmware content. do u have any clue about it. if u can help I would be appriciated.

  • Ammarbasalamah

    does still tampers with the software/hardware? :)

    • Ammarbasalamah


  • moxalis

    Thanks a bunch to everyone responsible for this, saved my Xperia Neo.

  • SupaGratefulGuest


  • Tudosemadalin

    my problem is that i unlock the bootloader, and then i updated over the air, and got brick’ed,wen i want’it to flash whit flashtool,wont conect
    i troed even whit test point but wont worck.

  • Tudosemadalin

    HELO my xperia arc won’t start, i tried to charge but wont conect to the flash tool, what can i do?

  • hamad

    whee is te folder “test” please repl  am at te final step but i cant find th “test” folder

  • JOHN

    my phone wont connect when its in flash mode
    !!! help 

  • Bagelisa

    The flash tool won’t open!!what do i have t do?

  • Telis

    Where is the folder ”TEST” ?

  • Vmobilehouse

    why can’t ……help

  • Junior

    It worked! I had unlocked the bootloader than i downloaded the updatet and my SE Arc died. Then i did this, it worked! Awsome, thanks alot! :D

  • http://androidflip.com Kuldeep Singh

    i also want to ask there is any relocker for Xperia play

  • Ka Nahl

    That’s a super tips ! does it works also on the play?