Unlocking the Bootloader of Sony Xperia Phones!! (Pre-requisite For rooting Sony Phones)

On the Specific Request, This is a Tutorial to Root Sony Android Phones, But the Procedure for Sony phones is a bit complicated in comparison to Samsung Phones.
First of all we have to unlock the Boot-loader of the Phone & then rooting can be done.
Advice: Don’t do it without reason!!
Before Unlocking the Boot-loader, Some pros and Cons:
Pros:

• You can flash custom ROMs/Kernels
• You dont need to worry if the new firmware can be rooted or not as with unlocked bootloader u can always ROOT ur device
• Sony gives sneak-peaks/preview builds of latest OS which requires unlocked bootloaders, as they did with Xperia 2011 line (they had ICS alpha/beta), so who knows may be Sony may give early builds of ICS (JellyBean???)
• Sony itself Supports unlocking Boot-Loaders.

Cons:

• Your phone can be brick, It steps not performed properly.
• It is not Possible for every phone, You have to check it via a Secret Code of service Menu: *#*#7378423#*#*
  • In your phone, tap Service info > Configuration > Rooting Status. If Boot-loader unlock allowed says Yes, then you can continue. If it says No, or if the status is missing, your device cannot be unlocked.
• If your phone Supports BootLoader Unlocking, Then, This procedure will wipe the /data partition of your phone, so you will loose all ur stored data, settings. SDCARD will NOT BE WIPED!!!
• DRM keys WILL be lost forever.
• Will Void the Warranty of your Phone. (So Try it on your Friend’s Phone first..

Pre-Requisites Before Unlocking the Bootloader:

• Make Sure Your Phone is allowed to be Unlocked.
• Your EMEI Number(Press *#06#), Write your Number at a Safe Place.
• Computer with Windows OS and Internet

Visit this Website (Its the Official Website of Sony)
Finally, Steps to be performed to Unlock the Bootloader:

1.     On your computer, click Continue at the bottom of http://unlockbootloader.sonymobile.com/instructions page to start the unlock boot loader process.
2.     Read through the information in the pop up window and click Yes, I’m sure, if you are still confident you want to unlock the boot loader.
3.     Read through and accept the legal terms. Click I Accept.
4.     Enter your name, a valid email adress and the first 14 digits of your phone’s IMEI or MEID number (remove the last digit if necessary). Click Submit. You can view the IMEI or MEID number by entering *#06# on your phone.
5.     The unlock boot loader key will be sent to your email. Save it for later use.
6.     Download and install the latest Android SDK from developer.android.com.
7.     Download and unzip this file. This is the standard android_winusb.inf-file, with a few lines of code added to enable Fastboot to support Sony and Sony Ericsson devices. Make sure you are running Google USB Driver package revision 4 or higher in your Android SDK. You can see current Google USB Driver package revision in the SDK Manager.
8.     Place the unzipped file in the usb_driver folder, located in the Android SDK > extras > google folder on your computer. Accept to replace the old android_winusb.inf-file with the new file. If you can’t find the usb_driver folder, please install the Google USB Driver Packager using the Android SDK manager.
9.     Turn off your phone.
10.     On your phone, push and hold the Fastboot button (turn phone off, hold menu button and plug in USB Cable) at the same time as you connect the phone to the computer with a USB-cable. The Fastboot button may differ between different phone models. See the Fastboot buttons page for more information on what button use on your phone.
11.     On your computer, you will be asked for drivers. Point to the usb_driver folder where you placed the android_winusb.inf-file, and select the Android Boot loader Interface-file.
12.     Open a command window and go to the tools folder within the Android SDK folder.
13.     Enter fastboot.exe -i 0x0fce getvar version, and verify that you get a response back (for example “0.3”). This means your phone is connected properly.
14. Final Step: If you perform this step, you will unlock the boot loader. This may void your warranty and/or any warranty from your operator. If you still want to unlock the boot loader of your phone, enter fastboot.exe -i 0x0fce oem unlock 0xKEY, where KEY is the unlock boot loader key you got in the beginning of this instruction. The boot loader should now be successfully unlocked.

Warning:
We haven’t Tested it yet, But Forums and Discussions Says, its Working
Newbies, Try it with Caution. Its not “Doctor Doctor”