1. Install Driver Sony Companion, FlashTool, Driver FlashTool (should install the full driver FlashTool)
2. Copy the original rom (stock firmware) .ftf format in the folder C: / FlashTool / firmwares (or in the folder you have installed)
3. Run the file FlashTool.exe with Win 32-bit, 64-bit Win FlashTool64.exe
4. Turn off the machine, hold the muffler and the cable pins (steps to the computer before installing the driver Flash mode and recognize the phone). Computer install drivers and alarm device connected to Sony's done, you can withdraw and leave the phone cable to one side and to the next step.
5. On your computer: in FlashTool the lightning and you select the mode selector Flashmode
6. Next, select the rom need up, select the necessary items depending on the requirements of Flash ROM and press
7. Wait 1 slice rom FlashTool finished unpacking and show up phone connection request, and you perform the following steps on the phone: hold down the silencer and connect the cable plug. When the phone is connected to your computer, start up rom FlashTool may drop lower volume key.
8. After you finish as shown FlashTool newspaper, cable and can draw power button 2 times to start the machine up.
9. Finish! Your phone was the original rom OK!
if you do not have the rom, look here : http://androidrom.net