Update: CM9 has come a long way since this article was written the first time. It’s pretty good rom now, not experimental anymore, so the Title of the post has been changed appropriately from “Cyanogenmod 9 (CM9) for Galaxy S2 is out — Very Experimental Build, Indeed!” to “Cyanogenmod 9 (CM9) for Galaxy S2″.
Installation guide is below, but lets see the compatibility and warning notes first:
This rom and guide below is compatible only and only with Galaxy S2 international version, model number i9100. It’s not compatible with any other device. Check your device’s model number in: Settings » About phone.
The methods and procedures discussed here are considered risky and you should not attempt anything if you don’t know completely what it is. If any damage occurs to you or your device, we won’t be held liable — you only will be responsible, you’ve been warned!!!
How to Install Cyanogenmod9 (CM9) on Galaxy S2 i9100 :
Installation guide has undergone a big change now. While it was required to be flashed using Odin earlier, it’s now a simple cwm-flash-ready zip file, making it hell lot easier and just the way it should be.
- Install a leaked Ice Cream Sandwich Galaxy s2 firmware first. Install the latest one right now (Feb 12, ’12) which is XXLPB.
- Also download the Gapps file and Faceunlock file from the page official page linked above. You will also get download links for modem files there. Well, ignore that, because you just flashed the latest modem in step 1 above. Gapps gets you Google apps and Faceunlock gets you face unlock feature of Android 4.0, both these files have to be flashed only after you’ve flashed CM9, and not earlier, and that these are optional.
- Transfer all files you downloaded in steps 3 and 4 above to your phone by connecting it to PC.
- Disconnect your Galaxy S2 from PC. Power it off — wait for 6-7 seconds after screen goes off.
- Boot into Recovery mode. Then, press and hold these 3 buttons together: VolumeUP+Home+Power till the Galaxy S2 logo shows up on screen. You’ll boot into CWM recovery soon enough. (In recovery, use Volume keys to scroll up and down and power key to select an option. Use back key to go back.)
- Do Wipe Data/Factory Reset
- Do Wipe Cache Partition
- Go to advanced and do Wipe Dalvik Cache
- Flash the rom file. Select install zip from sdcard » choose zip from sdcard » browse through sdcard and select the rom file you downloaded in step 3 above. Select “Yes – Install ______” on the next screen.
- Now, you can flash the Gapps and Faceunlock files. Select install zip from sdcard » choose zip from sdcard » browse through sdcard and select the Gapps file you downloaded in step 4 above. Select “Yes – Install ______” on the next screen. Repeat this process for Faceunlock file too.
- After you’ve flashed rom (and gapps and faceunlock files) you have to wipe stuff again from recovery’s main screen:
=> [Do Wipe Data/Factory Reset]
=> [Do Wipe Cache Partition]
- Now, select ‘reboot system now’ to restart the phone. Be patient while phone boots up, it may take between 5 to 15 mins for first boot.
- When the phone restarts, it will be running the Cyanogenmod 9 (CM9) with latest Android OS, v4.0.3. Check out your phone’s android version here -> Settings → About Phone.
- Enjoy! Don’t forget to thank Codeworkx and the CM9 team at the official development page here.
Share you thoughts and problems, if any, in comments below.