Although Samsung hasn’t released Android KitKat and Lollipop updates for Galaxy S2 I9100 due to some hardware issues, but no worries at all as you can still update your I9100 to enjoy latest Android 5.1.1 Lollipop on it.
Now as the Android 5.1.1 Lollipop custom ROM is available for your Galaxy S2 I9100, so I decided to help you guys by writing a comprehensive guide to install CM12.1 Android 5.1.1 Lollipop custom rom on your device. But before you proceed, let me clear it to you that you need to have your device rooted with CWM custom recovery installed on it. If so, then what are you waiting for?
- Download CM12.1 Android 5.1.1 Lollipop Custom ROM for S2 I9100
Steps to Install CM12.1 Android 5.1.1 Lollipop Custom ROM on Galaxy S2 I9100
Step 1: Place the downloaded rom zip file on your desktop after downloading is completed. Once done, connect your mobile to your computer and transfer the zip file to your phone SD card.
Step 2: Turn off your Galaxy S2 and boot it to recovery mode. For that, press and hold “Volume Up + Power” buttons.
Step 3: In recovery mode, first wipe the previous ROM by choosing “wipe data/factory reset” option. You can use volume button to navigate and power button to choose the option.
Step 4: Once data is erased, perform “Wipe cache partition” followed by “wipe dalvik cache” from advanced menu. After that, you will be ready to flash CM12.1 on your S2.
Step 5: Go back to main recovery menu and select “Install zip from SD card option” followed by “Choose zip from SD card” and browse for the transferred zip file on your mobile to start the installation process.
Step 6: The installation will take few minutes after which you will be required to reboot your phone.