Go through the easy guide given below to install the official CyanogenMod 12.1 (Android 5.1.1) on your Galaxy S2. Before you start installing the ROM, note that this is a nightly build, which means it is unstable, so you may come across some bugs while using the phone. However, if you are craving to get your hands on the Android 5.1.1 Lollipop on your Galaxy S2 go ahead and install CM12.1.
Note: The below procedure will wipe your device, so backup your phone data such as personal files, images, videos, messages, emails, contacts, apps, SMS, Contacts, Call Logs, Bookmarks, etc.
Install Official CyanogenMod 12.1 on Galaxy S2 Intl Variant (i9100)
Pre requisites: Your Galaxy S2 must be rooted and custom recovery like CWM or TWRP installed.
- Download the official CyanogenMod 12.1 [HERE] ROM zip file and Gapps [HERE] zip file for CM12.1.
- Copy both downloaded files to your phone’s SD card.
- Boot Galaxy S2 into custom recovery mode. To do so, turns off your phone, press, and hold Volume Up + Home + Power Key together.
- From custom recovery, wipe cache partition, data and dalvik cache.
- Select “Install Zip from Sd Card” and then select “Choose Zip from Sd Card” (Use Vol up/ Down keys for selection)
- Select CyanogenMod 12.1 ROM .zip file that you placed on your SD card, then select “Yes”, and let the installation process to complete. Do the same for Gapps zip file. After completing the installation, your phone will reboot (for the first time, it will take little long time). Enjoy Lollipop!
Troubleshooting
If your Galaxy S2 stuck in a boot loop (does not start up), power off it and boot it into recovery mode. From recovery, do wipe factory data, cache and dalvik cache. Once done reboot your S2. It will remove all the system junks as well as solve boot loop and restart issues. Any doubt, feel free to ask us. We hope our guide is easy to use. Please leave us feedback through comment box below.