You will need NetOdin
as well to flash the firmware
Step 1: On your S3 press then hold the Home/Power button until you see the S3 screen shows up "Rebooting..."
Step 2: Release the Home/Power button then quick Press it again 03 times.
Next step, you need to be a bit quicker.
Step 3: Use the Home/Power button to navigate to "Download (wireless)" option, then Press & Hold the Home/Power button to select. You have to be real quick otherwise your S3 will reboot.
Step 4: Press the Home/Power button twice, you will see the "[WPS Mode]" change to "[AP Mode]"
Step 5: Choose the Access point with the same name appears on your S3.
Step 6: Your S3 will show that it's been connected to the IP of your computer.
Step 7: Open the Odin, your S3 will show up.
Step 8: Choose the right file for each Option from the files you extract after downloading. Then press Start and wait for the PASS (15-20 minutes)