- Install Samsung Kies software (The drivers are needed for this process). HERE
- Your Phone must be detected by Samsung Kies.
- 7zip extraction tool HERE
- Backup your contents
- Factory Reset the Phone including Formatting the internal Storage. (remove Ext SDcard, just to be safe)
Go to www.sammobile.com and create a Free User account
Now Click on (3) Firmwares and Files Tab.
Scroll down the Firmwares and Files Page until you see the Selector below;
Type = Smartphone
OS = Android
Model = GT-I9300 - Galaxxy S III
Country = United Kingdom (Vodafone) - VOD
or United Kingdom - BTU ( for unbranded retail version)
Select the Firmware you require, either the Latest (top of the list) or an older version if you are Rolling Back.
The Firmware can take a long time to download, so time for a coffee or three!
You can also Download Odin3 Flashing Tool from this page. You will need this to Flash the Firmware.
The Firmware link will take you to a page like this...
The Flashing Tool link will take you to a page like this...
I will assume you have installed 7zip;
Right click on the Flashing Tool File,
choose Extract Here
Right Click on the Firmware and Choose
I would copy both the Flashing Tool Folder and the Firmware to the Desktop to make it easier to locate.
From the Desktop open the Flashing Tool Folder and locate...
Double left click on this file to RUN the software.
DO NOT change any settings on this Software!
Click on the PDA button ONLY!
do that now...
and browse to the Desktop and select the Firmware file you extracted earlier.
Now we need to put your Phone into Download/Odin mode.
Turn your Phone off.
Now follow the instructions in the picture below;
You will see a screen like the one below;
Press Volume UP to enter Odin mode.
This is Odin Mode;
Now connect your Phone to the PC with the Micro USB cable supplied with your Phone.
Wait for the Drivers to install...
The ID:Com window on the Odin3 software will highlight in Blue.
Now click on the START button.
Sometimes Odin can take a while to start flashing... WAIT! it will start!
DO NOT disconnect the Phone until it restarts...!
Quickly SKIP through the setup screens and FACTORY RESET AGAIN!
Now setup your phone following the onscreen prompts.
Rolling Back to The Base ICS ROMS:
Follow the flashing Guide as above;
When the phone restarts it may hang at the SAMSUNG logo.
If it does, pull the battery and wait 5 seconds. Then replace the Battery and enter Recovery Mode...
Volume Up + Home + Power; press and hold until the Galaxy S logo appears and release.
Select Wipe Cache Partition. (use vol up and down to navigate, press power to select)
Select Factory Reset from the Menu. (use vol up and down to navigate, press power to select)
The phone will restart properly.