Samsung’s mid-range smartphone, the Galaxy Grand 2 (SM-G7102), which is currently running on the Android 4.4.2 KitKat, can be updated to Android 5.0.2 Lollipop via unofficial CyanogenMod 12 custom ROM. Once you have updated your phone, you can experience the latest Lollipop features on your Galaxy Grand 2.
This unofficial Lollipop ROM is based on CyanogenMod 12 (Android 5.0.2) custom ROM and brings some of the key features of the new Lollipop operating system, such as the revamped Material Design user interface, animations and graphics. It will also enhance the phone’s performance with the new ART runtime and extend the battery life.
Today’s guide lets you know how to install unofficial CyanogenMod 12 (Android 5.0.2) Lollipop Rom on Galaxy Grand 2 SM-G7102. Though the ROM is almost stable, it has few bugs that have not fixed yet (for example, on second SIM incoming voice only, video recording does not save and boot animation lag). Go ahead and learn how install the new CM12 ROM on your Galaxy Grand 2.
a) This guide is for Galaxy Grand 2 SM-G7102 (International variant). Do not try the ROM on other models.
b) Your device has root access and latest custom recovery like CWM or TWRP installed. The recovery should support at least KitKat.
c) At least 80% charge on your phone
Important: Make a full backup of your system and every data. Follow the instruction at your own risk. We will not be liable if any damage occurs to your device and/or its components. It is recommended for technically talented users only.
3. Connect your phone to your computer and copy the downloaded CM12 ROM zip file and Gapps zip files to your phone’s SD card (Do not put the files inside a folder).
4. Disconnect your phone from computer, power off it and boot it into custom recovery mode. To do so, press and hold Volume Up, Home and Power buttons together.
5. Once your phone entered into CWM (or TWRP) recovery menu, perform a full system wipe. To do so, tap Wipe Data/Factory Reset option (use volume keys to navigate through menu and power button to select options)
6. Now, perform Wipe Cache Partition and then Wipe Dalvik Cache from advanced section.
7. Now, go to main recovery menu, choose Install Zip from SD card, select CM12 ROM zip and install it.
9. Once the installation is completed, go back to the main recovery menu and select Reboot System Now option.
Once your phone is rebooted (it will take at least 5 minutes for the first time), setup your device and enjoy Android Lollipop. (Source – Mukulsoni)