Last Updated on April 6, 2017 by Mathew Diekhake

The SlimRom team is delivering another ROM that’s suitable for the Samsung Galaxy S2 I9100 smartphone. The new custom ROM is based on Android 4.4.4 KitKat and is part of the SlimKat range. The team is working hard trying to deliver the next range of Lollipop custom ROMs. Until then this is the best we have to work with. In addition, we don’t know that the S2 will have anything under the Lollipop name for custom firmware, so you should take advantage of this new weekly build on your device.

As usual, you can’t install anything custom unless you have root access. Come back here after you have the system internals unlocked away from the default factory restrictions. You can read up on all the information we have available from this post. It directs you over to the official website.

SlimKat KitKat

We are running you through a list of essentials before starting the steps. That way you know what you are getting into and what you need before starting the guide.

  • You will be applying a factory reset during the installation process that completely wipes the data from the phone. That means everything that isn’t saved to the devices internal memory is lost. Save the phone contacts, text messages, pictures, movies, videos, music, gaming information and progress, applications and anything else you need such as the device settings to the storage by taking a Nandroid backup. You can take the Nandroid during the steps as soon as you enter recovery mode. We’ll give you the warning when you are about to wipe the ROM. That’s the ideal time to show the initiative and take the Nandroid.
  • You can take the backup without rebooting the phone by using the Online Nandroid backup app available from the Google play store.
  • You can enter recovery mode by using the reboot Manager application also available from Google Play. Use this if you are finding it difficult entering the mode by pressing the button sequence.
  • You may rely on the USB charging feature for most of the guide since we are connecting to the computer. Understand that if you are not using the USB charging your battery is draining accordingly. That means you must reserve enough battery power to last through until the end. Have about 55% from the battery icon on the status bar.
  • Verify the USB Debugging mode is enabled from the Developer Options menu. Check the Settings menu for the Developer Options menu.
  • The Developer Options menu is hidden during Android 4.2 Jelly Bean, but not KitKat or Lollipop. If you are running a version of Jelly Bean where the menu is not unlocked you can unlock it by tapping on the build number seven times. You also find the build number from the same Settings menu.
  • Have the latest USB drivers by Samsung so you are connecting to the computer successfully. You can test if you need to download them by accessing the phones data on the computer. An example of data is accessing the pictures from the drive.
  • You can download the Root and Unroot Pro application from the Google Play store if you want to change your device back to the stock Android. Understand that it takes away the root access and comes at a premium price. Otherwise you can wait for another official software update and flash the file manually to revert the device back to stock form.
  • Backup the data by using the built-in utility if you don’t want to take the Nandroid. Some people have their reasons. Or install any number of third-party application available from Google Play such as Easy backup, G Cloud backup and Helium.
  • Helium is a popular choice among the Droid fanatics this year for syncing the phone contacts.
  • You may use Samsung Kies for installing the up to date USB drivers if you don’t have them already. Just remember to disable the Kies utility before starting the guide.
  • Temporarily disable the security apps and programs from the phone and computer. Remember to turn them back on again before you start browsing the web after leaving here or else you risk being exposed to a Trojan Horse.

How to install SlimKat based on Android 4.4.4 KitKat on Samsung Galaxy S2 I9100

  1. Download the custom ROM 8.20 build here.
  2. Download the suitable Google Gapps package here.
  3. Transfer the files from the desktop to the internal storage of the phone.
  4. Disconnect the phone from the computer with the USB cable.
  5. Reboot the S2 up in recovery mode using the keys or the reboot manager app.
    – the button sequence is Home + Power + Volume Up.
  6. You are about to perform the factory reset. Now is the last chance to back up the OS.
  7. CMW Users:
  8. – select ‘wipe data/ factory reset’
    – select ‘install zip from SD card’, followed by ‘choose zip from SD card’
  9. TWRP
  10. – select the ‘Wipe’ option
    – select the ‘Install’ option.
  11. Upload the unofficial 8.20 ROM file.
  12. Repeat the steps for the Gapps pack.
  13. Follow the path back to the main recovery screen where you should select the ‘reboot system now’ option.

Think about applying a hard reset or a factory reset if the new ROM is causing problems. You must enter recovery mode and follow the steps to the factory reset option as shown in the steps above or try installing the simple factory reset app available from Google Play.