Install Android 4.0 CM9 RC1 on Galaxy S2 I9100

• Last modified: Tips

CM9 RC1 is soon going to be on all the Android geeks and people who love to install custom ROMs on their devices. The first release candidate version of CM9 released just a few hours ago and is already available for download around 37 Android devices (phones and tablets).

Have you ever installed custom ROMs before on your Galaxy S2 I9100? Or have tried CM9 Nightly builds or CM7 previously on your Android devices? Follow the steps carefully below so you can install CM9 RC1 on your phone.

Galaxy S2

Disclaimer: All the tools, mods or ROMs mentioned below belong to their respective owners/developers. We (TeamAndroid.com) or the developers are not to be held responsible if you damage or brick your device. We don’t have you on gun point to try out this tutorial ;-)

Make sure you have installed all your USB drivers for the Samsung Galaxy S II to connect it with the computer. Download Samsung Galaxy S II USB drivers! Apart from just the USB drivers, there are a few more things that you need to take care of.

1. You need to enable USB debugging mode. This helps to connect your Android phone with the PC. See here: How to Enable USB Debugging.

2. Your phone battery should be 80-85% charged. If your phone goes off suddenly because of battery, during flashing ROMs or installing mods and updates — your phone might go dead permanently. See here: How to Check Battery Percentage.

3. Backup all your important data that you might need as soon as your flash a new ROM, or make a backup for just in case, you never know when anything might go wrong. See below on how to backup data:

4. Your Samsung Galaxy S II should be factory unlocked. Additional instructions for locked Android devices will be added in the tutorial for unlocking devices.

Now, let’s proceed with the tutorial and install CM9 RC1 on your Galaxy S2 I9100.

HOW TO: Install CM9 RC1 on Samsung Galaxy S2 I9100

We have put together a detailed step-by-step instructions guide on how to install CM9 RC1 on Samsung Galaxy S2. If you are used to installing custom ROMs on your Samsung Galaxy S2, then this should not be any different for you. However, for beginners, you need to root your Samsung Galaxy S II and install a custom recovery. Please Google that up if you are unsure.

To Remember:

  • This tutorial is only for installing CM9 RC1 on Samsung Galaxy S2 I9100. Please do not try on any other Galaxy S2 variants.
  • Your phone SHOULD be rooted.
  • This tutorial will wipe out all your data. Proceed at your own risk.
  • Perform a Dalvik Cache wipe before proceeding from the recovery mode.
  • Samsung KIES will NOT detect your phone after installing CM9 RC1 Android 4.0 because it is a custom ROM.
  • ClockworkMod recovery should be installed from before.
  • Make sure you backup all your data in your phone before proceeding.

Complete Step-By-Step Instructions:

Step 1 - Download CM9 RC1 (cm-9.0.0-RC1-galaxys2.zip ) ICS for Galaxy S2 to your computer.

Step 2 - Connect and mount your Galaxy S2 USB memory on your computer using the USB cable.

Step 3 - Now copy/paste the downloaded cm-9.0.0-RC1-galaxys2.zip file to your SD card. Make sure the file is in the SD card root (not in any folder).

Step 4 - Then turn off your phone and disconnect from the USB cable.

Step 5 - Now to get in the recovery mode. Switch on the phone while pressing and holding the Menu + Power buttons.

Step 6 - Assuming you have ClockworkMod recovery, perform a full data wipe first. Then scroll down to “flash zip from SD card” and press the power button to select it.

Step 7 - Press the power button again and select “choose zip from sdcard”.

Step 8 -Now using your volume keys, navigate to the cm-9.0.0-RC1-galaxys2.zip file that you copied to your SD card and select it using the power button. Confirm the installation on the next screen and the installation procedure should start now.

Step 9 - After the installation completes, go to “+++++Go Back” and reboot the phone by selecting “reboot system now” from the recovery menu. The phone will boot now and it might take about 5 minutes to boot on your first time. So, please wait.

That’s it! Your Galaxy S2 should now have Cm9 RC1 installed on your phone! Go to Settings >About phone to verify.


  • Satish

    Hi there,

    Please advice what to do about Google Apps?
    Should I need to install them manually or flash some Gapps.zip file from Recovery as every other blog suggests?

    Thank you in advance.