How to use Sony Xperia Flashtool for hard resetting Sony Xperia devices. If you flash software to your device, your user data and downloaded apps will be erase. Make sure to back up important data. The data can not be recovered after flashing software. It also remove forgotten unlock pattern. If your Sony Xperia Bootloader is locked, you need to unlock it, check How to Unlock Sony Xperia Boot Loader.
How to flash software on your Sony Xperia:
- Make sure you have install Sony Xperia Flashtool on your Computer, If not yet see How to download and install the flash tool
- Open Emma from the Start menu of your computer.
- Connect a USB cable to your computer.
- Turn off your phone. Connect your phone to the USB cable while holding the flash key (for example Volume down). The flash key varies between models.
- Select the software you want to flash in the Service list. The tool automatically detects the phone model and lists available software versions, which are called Services in this flash tool.
- Click on Apply Service. The phone will now be flashed.
- When you have flashed your device, you can disconnect your phone from the computer. The first time you start your device after you have flashed it, the boot-up might take a little longer than normal.
Whatch this Video: How to use the flash tool
Source: http://developer.sonymobile.com/