UNLOCKING THE BOOTLOADER ON YOUR XPERIA

Bootloader Key

First of all Go to the official Sony website and follow the instructions given
You will get the bootloader key sent to your mail



SOME OF THE COMMON ERRORS YOU MAY FACE WHILE UNLOCKING THE BOOTLOADER

1.ERROR WHILE INSTALLING SDK ON UR PC

a. Errors related with JAVA are most probably related with bit version of the JDK and SDK you downloaded,Both should be of the same bit(32 or 64) otherwise errors such as

jvm.dll missing will be shown

2.PROBLEMS WHILE INSTALLING THE DRIVERS ON UR PC

http://developer.sonymobile.com/downloads/drivers/fastboot-driver/

Place the android_winusb 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.

i hope u have done the above step already!!!

Turn off your device.

On your device, push and hold the Fastboot button at the same time as you connect the device to the computer with a USB-cable. The Fastboot button may differ between different device models. See the Fastboot buttons page for more information on what button use on your device.

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.

now if the computer didnt ask u for the drivers u will have to install it manually

a.go device mananger
b.find ur sony device in the list and right click and chose update driver
c.chose browse in my computer
d.lemme pick up from a list of drivers
e.now select the ADB interface driver and click next

THE DRIVER HAS BEEN INSTALLED SUCCESSFULLY!!!!!!

3.ERRORS SHOWN IN THE COMMAND WINDOW

Enter fastboot.exe -i 0x0fce getvar version

now if you find this error its because you dont have fastboot.exe in the tools folder just copy it to the tools folder


now if you see "waiting for device" in the command window for a longtime its because you  haven't installed the drivers properly
follow step 2 (mentioned above)

if all the above is done you well get a version as response
eg:"0.3"

now run the command
fastboot.exe -i 0x0fce oem unlock 0xKEY

Where KEY is the unlock boot loader key you got in the mail

The boot loader should now be successfully unlocked!!!!!!!!!!!!!!!!!!