Easiest way to Unlock Bootloader All Sony Xperia Devices Included Docomo, AU and Softbank version

This post shows you the easiest method to unlock your Xperia Devices
Unlocking bootloader is one of the ways to customize your Xperia Devices. You have to unlock bootloader before rooting your phone, customize your phone kernel, etc. Although there are several Xperia phones which don't need to have bootloader access to grant root, granting bootloader access is still the most crucial thing if you want customize your Xperia freely. 
If you are using old Xperia devices, I highly recommend you to root your phones. Nowadays, every app that you install on your phone taking more storage, ram, and connectivity. This one is the main reason to root your devices.  Like I said before, you need to unlock your bootloader before rooting your Xperia devices. So, keep following this post.

In this post, I would like to show you how to unlock the bootloader of your Xperia devices.
You can use this method to unlock every Xperia device. without exception.
You need to prepare some software and files below.

Pre-Unlocking Bootloader Sony Xperia Devices

1. Make sure your Xperia is unlockable. To know that, dial *#*#7378423#*#*. Select "configuration" then look at the "bootloader unlock allowed" if it says yes, it means you're ready to the next step. If no, you can try to deactivate my Xperia feature. To deactivate it, open settings>security>Xperia protection. Make sure you turn it off. If bootloader unlock allowed status still "no" it means you can't unlock your Xperia's bootloader. Usually "no" appears for some bundled xperia smartphone such  docomo, au, softbank, t-mobile and many more.
2. Prepare a PC with Windows or Linux OS and USB cable. I recommend you to use USB cable that comes from the box of the phone. 
3. Download Sony Flashtool here. Make sure you install the driver too. if you have problem with installation, you can check the complete guide here. 
4. Dial *#06# on your Xperia to know your IMEI
5. Open Xperia official bootloader unlock request here
6. Select your device type then fill your IMEI. Don't forget to thick two agreements option.

7. Then click submit. The random code to unlock instantly appears. Don't forget to copy that.

If you got it all, we ready to go.

The Way To Unlock Bootloader All Xperia Devices

1. Open Sony Flashtool. For the first time you open flashtool. Make sure your pc connect to the insternet. So the flashtool can synchronize devices driver. 
2. Click BLU icon on the top corner. 

3. The pop up window will appear. It asks you to connect your Xperia to the PC. For Xperia that released on 2012 or above, hold volume down and connect your xperia to PC with USB cable. For below it, hold the back button and connect your xperia to PC with USB cable.
4. Once you connect it. the pop up should disappear. if it is not, it means your phone is not connected to the flashtool, the driver wasn't installed correctly.

4. The other pop up appear. It asks you to fill the IMEI and Unlock code that you have copied. Paste it! then click unlock.

5. Wait a sec! Until the log says "unlock finished". it it is not finished, unplug your usb, turn on the phone. Check the developer option, turn on usb the bugging and oem unlock permission. Then try again.

If you've done five steps above, it means your xperia bootloader is unlocked. To make it sure, dial *#*#7378423#*#* check the configuration option. Look at the bootloader status. If it say the same as before, it means the unlock was unsuccessful. if it say "bootloader unlock yes", it means your Xperia ready to join the party.

There are many ways to unlock your xperia devices but the way above is an official and safest way to unlock. So, I recommend you to use the method above than any other method. If you are not lucky to use method above you should try the other method instead. 

If you have a problem with the tutorial above, I would be happy to hear and answer your question in the comment section below.