Installing Android Lollipop 5.1.1 on Samsung Galaxy S2 GT-i9100

The Samsung Galaxy S2 GT-i9100 is still one of the most popular smartphones today. Although, official Android upgrades have been discontinued for this model it is quite easy to install Android Lollipop 5.1 on Samsung Galaxy S2 GT-i9100 using Cyanogenmod 12.1. This post describes the steps needed to install Android Lollipop 5.1 based on an existing Cyanogenmod setup, e.g. CM 11. Additionally, it shows which Google Apps package (“gapps”, Google Play Services) is supported for this setup and guides you through the processing of setting it up correctly.

Backup data

Before flashing the Cyanogenmod 12.1 ROM on your Samsung Galaxy S2 make sure to backup for data. We are going to format /system and all caches, thus erasing your user data and previous settings. Also, in order to install Android Lollipop 5.1 using Cyanogenmod 12.1 on your Galaxy S2 your device needs to be rooted. Have a look at a previous post Installing Android Jelly Beans on HTC Desire Bravo which is still valid to root your Samsung Android device. In case you don’t have Cyanogenmod installed on your Samsung Galaxy S2 GT-i9100 have a look the official CM installation guide for the Samsung Galaxy S2 first before continuing.

Install Android Lollipop on Samsung Galaxy S2 GT-i9100

Once you’ve backed up your data download the latest Cyanogenmod 12.1 nightly for the Samsung Galaxy S2:

and save it to your SD-card. Then, download the latest TK GApps Pico Modular Package:

Make sure to choose the Pico Modular Package as the Samsung Galaxy S2 has some memory constraints that probably will lead to errors for other package types. Don’t worry, the Pico Modular Package has everything you need to use your favorit Google services, such as Google Play Services and Google Play Store but in addition does not install all of Google’s applications you might not need. Below you find a comparison chart of the different TK Modular Packages available to get an overview of the applications available in the various packages:


Next, boot into Recovery mode (hold Home button, Volume up and Power simultaneously) of your existing CM 11 setup and execute the following steps:

Note: Make sure to backup your data first! Your settings and user data will be lost by executing the following steps!

  1. Wipe data/factory reset
  2. Wipe cache
  3. Mounts and storage => format /system
  4. Advanced => Wipe dalvik cache
  5. Install zip => Choose the CM 12.1 Nightly zip file you downloaded previously from your SD card
    1. do not reboot once finished
  6. Install zip => Choose the TK GApps zip file previously downloaded from your SD card
  7. Reboot

The first reboot will take some time, so don’t worry. After the reboot you now should have a working Android Lollipop 5.1 with compatible Google Apps on your Samsung Galaxy S2 GT-i9100! Simple, isn’t it?

Possible issues / hints

Do not use the Google Apps package officially provided by Cyanogenmod:


These will not work and you will end up with a message saying

Google Play Services, which some of your applications rely on, is not supported by your device. Please contact the manufacturer for assistence.

Also, you will possibly end up with a lot of crashes of Google Play Services and applications depending on this framework, like

“” and Google Apps has stopped working

Instead, use the TK Pico Modular Package as explained above. In case you get an error message while trying to flash TK GApps Pico Modular Package saying

* Incompatible GApps currently installed

make sure to wipe data and format /system first as explained above. TK Gapps can only be installed on top of an existing installation of TK GApps. Thus, you must wipe your system partition before installing any TK GApps package.

In case you have additional notes feel free to leave a comment. Have fun with the latest Android Lollipop 5.1 based on Cyanogenmod 12.1 on your Samsung Galaxy S2 GT-i9100!

4 thoughts on “Installing Android Lollipop 5.1.1 on Samsung Galaxy S2 GT-i9100”

  1. Followed instructions and installed, but get stuck in some form of loop or something when trying to boot.
    All I see is the little blue face and the flashing behind it. Even left in like that for 11hrs, no change, I’ve tried flashing several different firmwares, same problem.

    Anyone got an idea how to fix this?

  2. Your link says error “Over Quota
    This application is temporarily over its serving quota. Please try again later.” when Trying to download rom

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