Recently, I found a Samsung Galaxy S2, which was running on old Android Jelly Bean. I should try to install Android 5.1 on S2. I did some research, and in the end, I successfully installed Android 5.1.1 on it using CyanogenMod 12.1. So here is a guide for you guys as well.
Update: This guide no longer works to install Android 5.1. I have updated it to install Android 7 using LineageOS 14.1.
The general opinion is that the phone will get slow after getting the new operating system. But few people know that the latest operating system has better app optimization, it is efficient, and it can do stuff that consumes very little processing power after updating to Android 5.1.1. I noticed a significant performance boost in S2, running much faster than Android 4.1.2. Now, let’s move on to the guide on installing Android 5.1 on S2. I have used CyanogenMod 12.1, a stable version, to get Android 5.1 on S2.
To get Android 5.1 CyanogenMod 12.1 on your S2, you will first have to root your phone, then you will have to flash the firmware, and lastly, you will have to install the Google apps. I have covered each part in the guide below.
Pre-requisites:
- Download Samsung Drivers for Windows. (The link to download the file is under the main heading). These drivers are to be installed on your PC; they are essential for your PC to recognize your device correctly.
- Download ODIN from the official ODIN site. Or you can download the ODIN I used from this link.
- Download ClockWorkMod Recovery from here. Use the blue button to download the file.
- Download Gapps (Google Apps) from here. As this guide is for S2 and we are installing Android 5.1, select ARM and Android 5.1 in the third column and choose whichever seems suitable for you—I nano desired version.
- Download the SuperSU Rooting Zip file.
How to Install Android 5.1 on S2 [CyanogenMod 12.1]
- First, download the CyanogenMod 12.1, AOSP of Android 5.1, Gapps, and SuperSU rooting files from the above links and move them to your phone. You can place them in internal storage (Recommended) or external SD card. ( I have put them in an external SD card; that is why I selected zip from the SDcard)
- Once you have downloaded and moved the files to your phone, you must install custom recovery. Use this guide on how to flash ClockWorkMOD custom recovery on your S2.
- After you have installed Custom Recovery, turn off your phone and go to Custom Recovery. Press the Volume up, Home and power buttons simultaneously until you boot into custom recovery. First, you will notice the Samsung logo flash several times and see a yellow sign under it. Don’t worry about it. Keep on holding the buttons till you see the custom recovery menu.
- Now, you have to flash the SuperSu file to root your phone. To install from SD card -> Choose zip from SD card – > Now Select the CWM SuperSu.zip file. Let it flash. See the screenshot below.
Now, you have to install Android 5.1 on S2. The steps are the same: Goto Install from Sdcard -> Choose zip from Sdcard -> Select CM 12.1.zip file. It will take some time to flash.- Now you have to install Gapps. The steps are the same: Goto: Install from SDcard -> Choose zip from SDcard -> Select Gapps.
- Now, just a few steps left. Go back to the recovery menu and select wipe data/factory reset.
- After that, select the option “Clear cache partition“.
- Go to Advanced -> Select Wipe Dalvik Cache in the recovery menu.
- Now, go back to the recovery menu and select reboot system.
That’s it. Now your phone will reboot, and It will have Android 5.1
If you have issues installing Android 5.1 on S2 using CyanogenMod, let me know in the comments. You can also leave feedback in the comments if you have any queries. Feel free to ask us. Rooting and installing custom ROMS can sometimes lead to some issues, so if you encounter any problem while performing, follow these instructions on installing Android 5.1 on s2. Don’t freak out; ask me in the comments, and I’ll reply soon.
