First, get the Samsung MultiLoader (-> Tools).
Switch off your phone and remove SIM card & memory card, if installed.
Connect via Samsung USB data cable (drivers must be installed).
Hold down the Volume down key (on the left side) and the camera key (on the right side) simultaneously while switching the phone on. There should appear a service-message like ‘Samsung Bootloader v5.32 (…)’ on the display.
Now start the MultiLoader v5.33 and click on Port search. In bottom there must appear the port-nr of the USB/serial port used by your datacable, beside ready.
In the top, choose the right processor-type (in this case, ‘MSM6280′).
Below check Full Download.
Choose the file path for each of the files: ‘Amss’, ‘Rsrc1′, ‘Rsrc2′ (low) and ‘Factory FS’, included in the Firmware folder (unzipped).
Now click on Download. The updating process should start, and you should see a progress bar (also on phone display) indicating duration of download.
After a few minutes the phone should restart automatically 2 times and then the firmware update is complete.
Note:
If the phone doesn’t boot up after flashing firmware, repeat the whole process and try to flash the ‘Boot’ files also.
You can check the firmware version installed by dialling *#1234#.