[Sony Xperia S, Acro S, Ion] di3z_:
Give a chance to your Xperia S/SL to make show its capabilities. You can do many things like root, flash custom firmwares (ROMs) etc. with unlocked bootloader. But please be noted that unlocking bootloader of Xperia S voids its warranty provided by the manufacturer. But don’t worry warranty can be regained by relocking the bootloader & we will come up with an article for the same.

Let's Start..

:: Firstly Get & Note Down IMEI Code of Your Device. It can be Obtained by Dialing *#06# in Phone Dialer.

: :Charge Your Phone Upto 60% Battery Level So As To Ensure That It Doesn’t Turn Off During The Process of Bootloader Unlocking.

:: Temporarily Disable Your PC’s Antivirus Software As This Might Interrupt The Process.

By Assuming That You’ve Followed The Essential Steps Mentioned Above, You Can Now Move To The Further Part Of The Article Where Will Check on How To Unlock Bootloader.

Step 1 : Installation of USB Drivers.

:: Download Fast Boot Package With USB Drivers From The Attachements.

:: Switch Off Your Device & Connect It To The Computer Using USB Cable While Enabling Fast Boot Mode (Press & Hold Volume Up Button To Trigger Fastboot Mode). Windows Will Start Driver Installation As soon As You’ll Connect Your Device To The Computer While Keeping It In Fastboot Mode.

:: Now Extract The Fastboot Package Which You’ve Just Downloaded in Your PC.You Will Find 2 Folders Named As ‘fastboot’ & ‘usb_driver’.

:: Point Driver Installation Location To ‘usb_driver’ Folder.

:: Once Drivers Get Installed, Disconnect Xperia S From PC & Power On It.

Step 2 : Unlocking Bootloader.

:: Before Unlocking Bootloader, You Need To Check That if Your Device’s Bootloader Can Be Unlocked Or Not. For Checking Bootloader Status Dial *#*#7378423#*#* From Phone Dialer To Access Service Menu.Find Bootloader Unlock Status Over There. If It is Set To Yes Then Only You Can Unlock ::Your Device’s Bootloader Otherwise It’s Impossible To Unlock It.

:: After Verifying Bootloader Unlock Status Set To Yes, Go To Sony’s Official Bootloader Unlocking Site.

:: Scroll To The Bottom of The Page & Press Continue.

:: You Will be Prompted With The Message “Are You Sure ?”. Accept It By Clicking On “Yes I Am Sure”.(Assuming That You’ve Read It Properly). Then Accept The Legal Terms.

:: Now You’ll Get “Create Unlock Request” Page.Enter Your Name, Email Address & IMEI (Which You’ve Noted in Essential Steps Mentioned Above).

:: You’ll Now Get Unique Key Which Will Be Displayed On The Screen. Save It Safely As We Will Require It In Next Part Of The Article.

:: Open CMD in your computer and type "cd (location of Fastboot Folder)".

:: Again Connect Your Device To PC by pressing and holding the Volume Up button.

:: Now In Command Prompt (CMD) Type The Following Command :

fastboot.exe -i 0x0fce getvar version

:: If Value is Returned (It Should return 0.5), It Means Device is Connected Properly.

:: Type This Second Command Mentioned Below :

fastboot.exe -i 0x0fce oem unlock 0xKEY

:: Replace The KEY With The Unique Key Which You’ve Received Earlier and Hit Enter.

Congratulations !! You’ve Successfully Unlocked Bootloader.

Now Just In Case If You Get Any Difficulty While Unlocking Bootloader Procedure Mentioned Above, Do not Hesitate to contact me.