[GUIDE] Back up DRM Keys & unlock/relock Bootloader (Noob proof)

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By zxz0O0, Senior Member on 9th February 2014, 01:52 PM
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15th March 2018, 12:41 PM |#411  
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I can't restore, error find.exe
Hello, when i try to restore, my backup (in folder with backup 9.1.1) did not reach the phone, i am running android 4.4 i don0t remember in wich version i take the backup but please can somebody help me, i need to sell it but camera is so bad without drm. thanks a lot in advance!
20th January 2019, 07:00 AM |#412  
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How to retore DRM and relock BootLoader.
Originally Posted by zxz0O0

This is a step by step tutorial on how to back up your DRM keys (TA Partition, to revert to factory state in case of warranty issue) and unlock the bootloader. After unlocking the bootloader you will lose your DRM keys so it's good to make a backup of it (it's optional though). Basically no DRM keys means no warranty and unlocked bootloader means no warranty. Read also here for additional info:

Make sure to read the 'Questions' (bottom of the post) if you encounter any problems!

First of all you need to have root access to backup your DRM keys.

Follow this thread to get root:

Old method:

Follow these steps, after that you will have an unbranded UK KitKat (4.4) firmware with root access (if you rather want JellyBean 4.3, check out 'Questions' down below). Thanks to Darkimmortal for the steps (I added some steps and made it easier to follow).

Take a backup of your phone because it will be wiped!

Video by @shem2409

  1. Contribute to this thread:
  2. Install Z1 Compact USB drivers ( )
    It's possible that Z1 Compact drivers are already installed, if you have installed Sony PC Companion.
  3. Install Flashtool ( )
  4. Install fastboot & flashmode drivers from Flashtool (go to the installation directory and open the folder drivers/) (note: if you have Windows 8.1 64bit you need to disable Driver Signature check: Link)
  5. Download SuperSU and put on your SD card (do not unzip) ( )
    Note: There might be problems with large SD cards (32GB and bigger). You can also put the files on your internal storage: Follow steps 5-7 after step 11.
  6. Download latest Z1C-lockeddualrecovery(...) and put on your SD card (do not unzip) ( )
  7. Download and put on your SD card (do not unzip) ( | mega mirror )
  8. Download SO-02F_14.1.H.1.281_docomo.ftf and put it in the installation directory of flashtool in the folder firmwares/ ( | share-online mirror | mega mirror )
  9. Open flashtool, select Flash => Flashmode and flash SO-02F_14.1.H.1.281_docomo.ftf (select Wipe [Check ALL] and Exclude [Check TA, BASEBAND, FOTA])
  10. Wait atleast 30 seconds then power off your phone, hold volume down and plug in your USB cable (your phone will boot in flashmode)
  11. After flashtool flashed the firmware successfully, remove the cable and power on the phone (will take some time) and go to Settings => 'About phone' and press 7 times on 'Android Build'. This will unlock the Developer options in Settings. Enable USB debugging under Developer options and check 'Unknown sources' under Security.
  12. Now flash C6903_14.1.G.534_ianford10_UK Unbranded_modified.ftf in flashmode (boot phone in flashmode again) (select Exclude [Uncheck ALL] and Wipe should be empty) ( | mediafire mirror | share-online mirror )
  13. Start your phone normally and plug in your USB cable (screen will be black, this is normal and it will stay like that until you finish step 16)
  14. Download and extract Z1C-lockeddualrecovery(...) Then run install.bat and select option 3 [Installation on unrooted ROM] ( )
    Note: This is actually a different file as the one you downloaded on step 6. You're supposed to run this one here on your computer.
  15. After the process is finished and you get a confirmation that your device is rooted, hold Volume Up and hold the power button. After the phone vibrated 3 times it will shut down. (This is force power off)
  16. Flash D5503_14.3.A.0.681_Generic_UK-nosystem.ftf in flashmode (boot phone in flashmode again) (select Wipe [Uncheck ALL] and Exclude [Uncheck ALL]) ( | mega mirror )
  17. Go to the Recovery Menu. To do that, power off your phone. Then power it on again. After the vibrate and the green LED turns on, hold Volume Up (LED will turn violet). PhilZ Touch recovery will open.
  18. Try to flash SuperSU zip. If it doesn't work, switch to TWRP recovery (Volume Down) and try there.
  19. Now format /system (located under Mounts & Storage) (Important: Do NOT reboot until advised so or you will have to start again)
  20. Do a factory reset in the Recovery Menu
  21. Install the following files in this order (Important) (see steps 5 - 7)
    2. Z1C-lockeddualrecovery(...)
    3. UPDATE-SuperSU-v1.(...).zip
  22. Optional: Update to the latest firmware with this guide:
  23. Reboot your phone
  24. Congratulations, your phone is now rooted (bootloader still locked)

DRM keys Backup
Now since your phone is rooted you can proceed with backing up your DRM keys (TA partition). Follow these steps:
  1. Enable USB debugging on your phone (go to Settings => 'About phone' and press 7 times on 'Android Build'. This will unlock the Developer options in Settings. Enable USB debugging under Developer options and check 'Unknown sources' under Security.)
  2. Download Backup TA and start Backup-TA.bat ( )
  3. Select Option 1 (Backup) to backup your TA partition
  4. After the process succeded your backup will be in the folder backup/ (Make a backup of the backup!)
  5. Congratulations, you have now a backup of your DRM keys. You can also use Backup TA to restore your TA partition. It is recommend to have the same firmware when restoring as you had when you backed it up (see here: )

Unlocking bootloader
Now if you have a backup of your DRM keys you are ready to unlock the bootloader. You need to have an unlocked bootloader to install Custom Roms, test builds, etc.

Make a backup because your SD card will be formatted!

Follow this guide to unlock the bootloader:
Yes, it also works for Z1 Compact, all the steps are the same. You can skip installing the drivers since you should already have them from the steps above.

Relock bootloader only
If you want to relock your bootloader (e.g. for downloading official sony updates in Sony Update Service) you can do so with flashtool. This only works if you already unlocked the bootloader with the official method.
Note: This does not restore the DRM keys. If you have a warranty issue you should restore your TA parition (which will relock your bootloader and restore DRM keys) with Backup TA.
  1. Open flashtool
  2. Click on the BLU icon
  3. Connect your phone in flashmode (hold volume down and plug in your USB cable)
  4. Flashtool will ask you about the device model, choose Sony XPERIA Z1 (if Z1 compact is not in the list)
  5. Flashtool will read your IMEI and your unlock code. Check if those are correct (compare unlock code with the one you received by email from Sony when you unlocked the bootloader)
  6. Flashtool will save the unlock code in its program folder under custom/mydevices.
  7. Click "Lock bootloader" (-> If you want to unlock it again, repeat the steps (it will automatically detect that your bootloader is locked))

  • How do I power off my phone if the screen is blank or the phone is not responding? (Force power off)
  • My Antivirus detects flashtool as malware?
  • How can I verify if my bootloader is locked/unlocked?
  • I am currently on firmware x, can I still follow this guide?
  • How to remove recovery and root?

Questions from old guide:
  • Is my language still available after flashing this English firmware?
  • After flashing docomo firmware, my phone is not recognized anymore?
  • I don't like KitKat (4.4), what can I do to get on JellyBean (4.3) rooted?
  • My browser saved the ftf files as *.zip. Is it ok to just rename them to .ftf?
  • I finished the guide but I still have some leftovers of DoComo (apps, sheep sound)?
  • I don't want to flash the UK firmware, are there any other firmwares?
  • I can't access the flashable files in recovery, there are error messages in recovery "can't mount"?
  • Flashtool does not recognize the firmwares, even though I put it into the correct folder?
  • Why is the rooting procedure so damn complicated?
  • How do I install the Z1 Compact USB drivers? There is no exe file?
  • I can't install the Z1 Compact drivers because my phone doesn't boot?
  • I can not install dualrecovery, Windows says it's unable to install MTP drivers?
  • I can not install dualrecovery, it says "Waiting for device to connect"?

Many thanks to:
  • Darkimmortal
  • RyokoN
  • [NUT]
  • DooMLoRD
  • All the great devs that made these tools
  • raph84

Hi everyone, I have the DRM backup my Xperia Z2, but I want back to stock rom, restoring my DRM Keys and relock BootLoader.

can help me, please?
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