Samsung Galaxy S2 – I9100G: Flashing CM9

I have posted a couple of weeks back that CM9 nightlies for Galaxy S2 I9100G has begun. Now, I have had the opportunity to flash my brother’s Galaxy S2 I9100G. Overall, the process was quite easy but maybe a little nerve wrecking for beginners.

The official update instructions can be found here along with the known issues and FAQs.

Preparation:
1. Have at least 60-70% battery life before attempting any flashing of firmware.
2. Have at least 1GB of free space left (for backup purposes) before flashing.
3. Have a PC with Samsung drivers or KIES installed (but don’t launch KIES). You can get the latest Samsung Drivers here.

Steps:
1. Backing up your important data.
–  Recommend using Google account to backup your contacts and SMS Backup & Restore app to backup SMS. There is also a Call Log Backup & Restore app should you need to backup that. If you don’t fancy using Google account to backup your contacts, there are plenty other methods or apps to backup your contacts. But I recommend staying away from Super Backup as it has caused failures on my sister’s Galaxy Ace when moving to CM7. Also, make sure your app is updated before backing up your data.
–  If you should want or need to use Titanium Backup app, you may do so but restore apps and data at your own risk. It could cause Force Close (FC) on CM9 upon restoring. Do not restore system data.

2. Download the relevant files. Links are provided below:
Official ICS for I9100G (only needed if you are not on ICS bootloaders or unsure which bootloaders you are on) –> You will need to sign up and login.
Odin for I9100G (only needed to flash the official ICS for I9100G)
Heimdall Suite 1.3.2 for Windows (needed to flash in the CWM kernel) –> Heimdall Sutie for other OS can be found from the Official Update Guide.
-> You may need the Microsoft Visual C++ redistributable package for Heimdall Suite to run.
CWM Kernel from Codeworkx
Galaxy S2 I9100G CM9 Packages
Latest Gapps package for CM9

3. If your phone is already on ICS bootloaders, you may skip this step. Otherwise, you will need to update your phone to the official ICS release from Samsung first.
–  Power off your phone.
–  Power on while holding down the Menu button and Vol Down button. This will boot it into Download mode.
–  Launch Odin on your PC and connect your phone to the PC using the USB cable.
–  Wait for the ID:COM section to turn yellow.
–  Click on the PDA button in Odin and select the official ICS file. Do not change any other settings in Odin and do not check Repartition.
–  Click on the Start button in Odin.
–  Once done, your phone will reboot itself and now you should be on ICS. If you are unsure, check the Settings -> About phone -> Android version and it should say 4.0.x
Note: On occasions, the downloading process may have gotten stuck. If you do not observe any progress in Odin’s message window after a while, you can try to reboot the phone. Generally, you should be able to reboot the phone into Download mode and try again.

4. If your phone already has a proper working CWM, you can skip this step. Otherwise, you will need to install a CWM kernel onto your phone first.
–  Untar the CWM kernel into the Heimdall Suite’s folder. You should get a zImage file.
–  Power off your phone.
–  Power on while holding down the Menu button and Vol Down button. This will boot it into Download mode.
–  Run zadig.exe from the Heimdall Suite’s drivers folder.
–  From the menu, select Options -> List All Devices and from the drop down menu, you should see something like Samsung Serial Device. Select that one.
–  After installing the driver, you would need to launch a command window to send a command.
–  Press the Window key on your keyboard and enter cmd into the Search programs and files.
–  In the command prompt, navigate to the Heimdall Suite’s folder and type:
heimdall flash –kernel zImage
–  Once done, the phone will reboot itself and now you will have CWM recovery.

5. Copy the CM9 and Gapps files onto your phone or microSD card. Usually I’ll create a folder like “/sdcard/All_<phone>_ROMS” and place all the files I need in there. I prefer to use a folder starting with A so that you don’t have to scroll too far later on.

6. Install CM9 and Gapps
–  Power off your phone.
–  Power on while holding down the Menu button and Vol Up button. This will boot it into CWM Recovery mode.
–  In recovery mode, use the Volume keys to navigate up and down the list, the Power button  is used to select/enter.
–  Optional: Navigate to “backup and restore” to create a backup. This can take some time so don’t be alarmed.
–  Navigate to and select “Wipe data/factory reset“. This is done to wipe the old data from the Samsung ROM.
–  Navigate to and select “Wipe cache partition“. This is done to wipe the old data from the Samsung ROM.
–  Navigate to and select “Install zip from sdcard“, then “Choose zip from sdcard” or “Choose zip from internal sdcard” (depending on where your files are stored), navigate to your folder and select the Galaxy S2 I9100G CM9 package. This can take some time so don’t be alarmed.
–  Optional: Navigate to and select “Install zip from sdcard“, then “Choose zip from sdcard” or “Choose zip from internal sdcard” (depending on where your files are stored), navigate to your folder and select the Gapps package. This can take some time so don’t be alarmed.

7. Reboot the phone after installation is complete.
–  Navigate back to the main screen of CWM Recovery and select “reboot now“. The first boot up will take some time but eventually, you will reach the Google account setup screen. If you didn’t install the Gapps package, you will not see this. NOTE: Gapps package will NOT install the GMail app. You will need to download GMail app from the Google Play Store.

8. Congratulations. Your Galaxy S2 I9100G is now on CM9. Reinstall your backup applications and restore all the SMS, contacts and any other data that you need to your phone and enjoy your new CM9.

If you have any questions, feel free to contact me. I will do my best to help.