The official method to unlock bootloader for Sony Xperia M4 Aqua is not available anymore. Here is a simple guide using which you can unlock your bootloader with the Flashtool available for Sony Android devices. Like the official method, you will need to acquire the unlock key from the official Sony website. Once you have the key, you may proceed with unlocking the bootloader using the fastboot application listed in this tutorial.

This remains an unofficial method. Hence, you will need to be cautious about it. This will unlock the bootloader on your Xperia Aqua M4. To begin with the unlocking process on your device, first, make sure you abide by the requirements listed below. First, open the fastboot and try the BLU option to unlock the bootloader. If it fails, continue with the tutorial below. Read the full tutorial first and then proceed.

Warning: Warranty may be void if you unlock the bootloader on your device. We at DroidViews won’t be liable for any damage to your device whatsoever. We won’t be held responsible if you brick your device. Reader’s discretion is advised.


  • Download | Flashtool for Sony Xperia devices on Windows, Linux and Mac OS


  • This procedure is applicable for Xperia Aqua M4 only. Do not try it on any other device.
  • Set up ADB and Fastboot on your computer. You can download the full Android SDK from here, or get the quick ADB and fastboot installer from here. For Mac or Linux OS, click here.
  • Install Sony USB Drivers on your computer.
  • Open Settings> Developer options and enable USB Debugging on your device.
  • Get the fastboot tool from the download section.
  • Go to Developer options and enable Allow oem unlock if applicable.
  • You will need the Key to unlock your device. To do this, go to Sony website from here. Choose M2 or M and complete the steps to get your KEY. You can find the serial number of your device at Settings – About phone – Status. Scroll down to see the serial number.

Backup Apps and Data
While this process may not wipe any of your data, a backup is highly recommended. However, unlocking bootloader may sometimes remove apps and data. Make sure you backup your apps, data, etc. It will be helpful in case anything goes wrong. You can use the Sony PC companion for this purpose.

How to Unlock Bootloader on Xperia M4 Aqua

This will unlock the bootloader on your Xperia Aqua M4. To begin with,  first open the fastboot and try the BLU option to unlock the bootloader while your device is connected and setup as per requirements. If it fails, continue with the tutorial below. Read the full tutorial first and then proceed.

  1. Download and install the Flashtool from above.
  2. Navigate to the folder where the Flashtool is installed. (Example: C:/Flashtool)
  3. Now open the folder named Custom and navigate to the folder named Mydevices. (For Flashtool version it exists. If it doesn’t, you may create it.
  4. In the newer Flashtool, you will need to put the folder in “C:\Users\<username>\.flashTool\registeredDevices” in step 3. (This means that, you will have to pick the default for your flash tool home folder otherwise you can choose manually)
  5. Now create a new folder and rename it with your device code. Refer to note 2 on how to find your device code below.
  6. Now open this folder created previously.
  7. Create a new text file and rename it as ulcode.
  8. Paste your unlock code and save it in the text file
  9. Open Flashtool and try the BLU option again.

Note 1: Step 3 and 4 will require you to verify the Flashtool version and act accordingly.
Note 2: In step 5, you will need the device code. your device code is showed in the log when you click the button BLU, at the “Current device”, after your device model.
Search a line like:

 09/045/2015 23:45:08 - INFO - Current device : C2104 - AB100C2DE3 - 1272-4136_R5B - 1269-5420_15.3.A.1.17 - WORLD-a_15.3.A.1.17

For instance, if the device code is AB100C2DE3, then this should be the new folder name in step 5.

Once the process is complete, bootloader on you device should now be unlocked. Now you may proceed with installing TWRP or similar custom recoveries on your Xperia Aqua M4. Check out this page for more information.

For queries, comment down below. If we have helped you, then like and share us on social platforms. If you need help with other devices, let us know.


  1. cant find the device code and not to sure where to put the folder I have the newer version of the flash tool and have acquired the code from the xperia site

  2. I have the same problem. It does not display the line “INFO – Current device : ….” Therefore I cannot obtain my device code and complete the guide.

  3. i can’t find Allow oem unlock in developer option. When i try to click on blu button, the flashtool say to unplug the phone and plug again pressing volume down button…. but nothing really happen…. This guide don’t works!

  4. here my log of fastboot

    02/030/2016 12:30:23 – INFO – Flashtool Version built on 04-10-2015 21:00:00
    02/030/2016 12:30:23 – INFO – Executing search strategies to find proxy selector
    02/030/2016 12:30:24 – INFO – No proxy found for IE. Trying next one
    02/030/2016 12:30:24 – INFO – No proxy found for firefox. Trying next one
    02/030/2016 12:30:24 – INFO – No proxy found for java. Trying next one
    02/030/2016 12:30:24 – INFO – Syncing devices from github
    02/030/2016 12:30:24 – INFO – Scanning devices folder for changes.
    02/030/2016 12:30:47 – INFO – Pulling changes from github.
    02/030/2016 12:30:48 – INFO – Devices sync finished.
    02/030/2016 12:30:50 – INFO – Please connect your device into flashmode.
    02/030/2016 12:30:54 – INFO – Device disconnected
    02/031/2016 12:31:27 – INFO – Opening device for R/W
    02/031/2016 12:31:28 – ERROR – Drivers need to be installed for connected device.
    02/031/2016 12:31:28 – ERROR – You can find them in the drivers folder of Flashtool.
    02/037/2016 12:37:18 – INFO – Processing loader.sin
    02/037/2016 12:37:18 – INFO – Checking header
    02/037/2016 12:37:18 – ERROR – Processing of loader.sin finished with errors.
    02/037/2016 12:37:18 – ERROR –
    02/037/2016 12:37:18 – INFO – Your phone bootloader cannot be officially unlocked
    02/037/2016 12:37:18 – INFO – You can now unplug and restart your phone

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