Flashtool is like using PC-Companion(PCC) or Sony Update Service (SUS) for MAC users Sony Bridge to flash a specific FW. It uses a .ftf file extension and works on phones with or without unlocked bootloader. It can only flash stock roms. You get into flashtool mode by turning off your phone and pressing specific hardware key button, and then connecting the USB cable to your phone. Done correctly and you should see a green light on the power.
Posted on Monday, 4 February 2013