Install Android 5.1 Lollipop on Galaxy S2 GT-I9100 / Galaxy S GT-I9000 with OmniROM

The latest Android 5.1 is rolling out for most of the Samsung’s new flagships now a days but there is no news that if Samsung will provide software updates to their old smartphones like Samsung Galaxy S2 (GT-I9100) and Galaxy S (GT-I900).  Thanks to the custom ROMs developers, if you have the Galaxy S2 or Galaxy S devices then you are lucky that you can now taste Android 5.1 Lollipop on your phone with OmniROM. The OmniROM is a mixture of great features adopted from CyanogenMod, SlimROMs and ParanoidAndroid ROM. This awesome ROM is based on the original AOSP which comes with stock Lollipop experience.

So if you are ready to install the latest Android OS on your Galaxy S2 or Galaxy S then we have a detailed guide on how to update Galaxy S2 and Galaxy S to OmniROM based on Android 5.1 Lollipop.

Do note that OmniROM is developed by the third-party developers, not officially released by Samsung. You might face some bugs or not functioning features. You’ll need to have a custom recovery already installed on your phone in order to flash the ROM and Google Apps .zip files on your device.


This tutorial containing the OmniROM download links and instructions can be used only for the Galaxy S2 GT-I9100 and Galaxy S GT-I9000 (international variants). Check the model number of your device first by navigating to Settings > About Phone.

Warning: will not be held responsible for any kind of damage occurred to your Galaxy S2 or Galaxy S during or after the installation of Android 5.1 based OmniROM. Proceed at your own risk.

Before Getting Started:

  • Take a proper backup of all your existing data and settings before proceeding to the ROM installation guide using a recommended custom recovery like CWM or TWRP.
  • Download and install the correct USB Drivers for the Galaxy S2 or Galaxy S5 on the PC.
  • Enable USB Debugging Mode on your device by navigating to Settings > Developer Options.
  • Your device should be rooted with CWM recovery installed on it.
  • The bootloader of the Galaxy phone must be unlocked.
  • Make sure that the battery level of your device should be charged at least about 80%.

Required Files:

Steps to Install Android 5.1 Lollipop on Galaxy S2 GT-I9100 and Galaxy S GT-I9000 via OmniROM:

Step No 1:- First, download OmniROM Android 5.1 custom ROM for Galaxy S2 / Galaxy S I9000 on the desktop of the PC.

Step No 2:- Connect the Galaxy S2/S to the PC using its USB data cable and mount its USB memory storage.

Step No 3:- Copy the OmniROM Android 5.1 custom ROM .zip file that you’ve already downloaded from the above link, to the root folder of your SD card on the phone.

Step No 4:- Disconnect the phone from the PC and switch it OFF to boot it into Recovery Mode.

Step No 5:- Switch ON your device while pressing and holding Volume Up + Home + Power buttons at the same time to enter into Recovery Mode.

Step No 6:- While your device is now in CWM Recovery, perform wipe data/factory reset, wipe cache partition and wipe dalvik cache also by navigating to Advanced > Wipe Dalvik Cache.

Note:- wipe dalvik cache will help you to prevent boot loops and other errors while ROM installation.

Step No 7:- Go back to the main Recovery Menu and choose install zip from SD card → choose zip from sdcard.

Step No 8:- Navigate to the Android 5.1 custom OmniROM .zip file which you’ve already transferred to the SD card of your device previously. Select the ROM .zip file using the Power button and confirm the installation to begin.

Step No 9:- Navigate to +++++Go Back+++++ once the installation is completed. From Recovery Menu, reboot your device by selecting reboot system now.

Your Galaxy S2 I9100 or Galaxy S I900 will be rebooted and may take about 4 to 5 minutes to boot for the first time after installation.

Done! You’ve successfully updated Galaxy S2 I9100 or Galaxy S I900 to Android 5.1 Lollipop via OmniROM custom build.

Let us know in the comments section below if you have any query or problem regarding the above tutorial to install Android 5.1 Lollipop based OmniROM on your Galaxy S2 or Galaxy S.

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