39 Kudos
Don't
move!

This guide is for the Sony Xperia Arc and the Sony Xperia Arc S.
This works with both LOCKED and UNLOCKED bootloaders.

However, this process is more suitable to locked bootloaders, because if you have an unlocked bootloader, you can just use Sony’s Official Flash Tool

Firmware 4.1.B.0.587, 4.1.B.0.431 or 4.0.2.A.0.62

Prerequisites:

On your phone first:

  • Enable USB Debugging
    • Settings/Developer Options/USB Debugging
  • Enable Unknown Sources
    • Settings/Security/Unknown Sources

Flashtool

  • Install and open Flashtool
  • Drag and drop the .ftf file you downloaded earlier
  • Leave all options default

On your phone

  • Disconnect from USB
  • Power off, wait 5 seconds
  • Press and hold the back button
  • Plug in the USB
  • Wait until Flashtool starts doing it’s magic, release the back button

After Flashtool is done

  • Disconnect from USB
  • Start phone
  • Done