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.

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