Samsung s3 gt-i9300

The following procedure explains how to reset || update a Samsung Galaxy S3 using OFFICIAL firmware from Samsung.

Why update?

• Sometimes the update is not broadcast by our phone carrier
• Your phone might bug and you want to reset it to its original state

Preparations

You'll need the following files:

• Download Samsung "Odin" for Windows. I'm using [ Odin v3.09]
• Download "CF-Auto-Root" to get Root access on your Samsung. [version 2014-01]
• Download the "recovery ClockWorkMod Touch", required to save the phone partitions
• Download the latest S3 GT-I9300 firmware for your country.

  --> [ Click here to get the I9300XXUGND5 for Nordic market]. If you have another model, please check: http://samsung-updates.com/ 
  --> Unzip the archive to get the ".md5" file

ROOT phone

• Launch Samsung Odin
• Click "PDA" or "AP" and select the "CF-Auto-Root-m0-gti9300.tar.md5" file
• Shut down phone
• Restart phone in "Download" mode: hold Volume Down + Home + Power during 5 seconds
• Connect the phone to your PC using USB wire
• Wait for "Odin" to detect the phone... A blue|yellow block will appear: ID-COM
• Click on "flash"

...The phone should restart automatically after 5 seconds...

Install recovery

• Launch Samsung Odin
• Click "PDA" or "AP" and select the "recovery-cwm-touch-6.0.1.2-i9300.tar" file
• Shut down phone
• Restart phone in "Download" mode: hold Volume Down + Home + Power during 5 seconds
• Connect the phone to your PC using USB wire
• Wait for "Odin" to detect the phone... A blue|yellow block will appear: ID-COM
• Click on "flash"

...The phone should restart automatically after 5 seconds...

Backup EFS partition

Now that the phone is rooted you must backup the EFS partition. This partition is very small but of the utmost importance: it contains the IMEI + simlmock ! This partition cannot be update - should no problem should occurred - but we're never too careful!...

• Install a new application from the "Play store": Boite à outils SGS

https://play.google.com/store/apps/details?id=com.boiteoutilssgshelroz

• Launch application and grant it 'root' rights
• Click on the "EFS" tab
• Click on "Sauvegarde EFS" (it's the 1st option)

!!Do NOT touch anything else in that application!!

Now you have to backup the EFS file on your computer: /sdcard/boite_a_outils

Backup APN data

It's often a mess to configure 3G | 4G. So you better save your APN configuration!

Go to:

• Settings > Connectivity > Others
• Click APN and edit the current configuration
• Write everything on a sheet of paper

Backup data (optional)

• Shut down phone
• Restart phone in "recovery" mode: hold Volume Up + Home + Power during 5 seconds
• Click on "backup and restore"
• Click on "choose backup format"
• Select "tar"
• Select "backup" |or| "backup to external sdcard"

The backup can take several minutes... Let the phone do its job!

Clean data (optional)

• Shut down phone
• Restart phone in "recovery" mode: hold Volume Up + Home + Power during 5 seconds
• Click on "Wipe data/factory reset"
• Click on "Wipe cache"

Upgrade phone

At last, you can now upgrade / restore your phone.

• Launch Samsung Odin
• Click "PDA" or "AP" and select the "I9300XXUGNA5_I9300[...].tar.md5" file
• Shut down phone
• Restart phone in "Download" mode: hold Volume Down + Home + Power during 5 seconds
• Connect the phone to your PC using USB wire
• Wait for "Odin" to detect the phone... A blue|yellow block will appear: ID-COM
• Click on "flash"

!! This will take some time !! Be patient !! Up to 20 / 25 minutes depending on the USB speed !!

...The phone should restart automatically at the end... ...You should see Android update process...

Root phone again (optional)

If you like to get root access again you can see the previous [#Root phone] section

Sources

• Galaxys-team.fr: http://galaxys-team.fr/viewtopic.php?f=86&t=41972
• SamMobile.com: http://www.sammobile.com/firmwares/database/GT-I9300/HTS/
• Application 'Boite à outils SGS': https://play.google.com/store/apps/details?id=com.boiteoutilssgshelroz
• PlanetGalaxy.com: http://www.planetegalaxy.com/forum/i9300xxugnd5-pays-nordiques-23-05-14-t28284.html