If you are still using legendary Samsung Galaxy S2 (model GT-I9100), released in 2011, you probably faced the question: which version Android works on it out of the box, and can it be updated to modern standards? This smartphone became one of the most popular flagships of its time, but more than ten years have passed since then - an era in the world of mobile technology.

Officially Galaxy S2 supported updates only up to Android 4.1.2 Jelly Bean, but enthusiasts and developers of custom firmware did not leave the device unattended. In this article we will look at:

  • 📱 What version of Android was pre-installed and what updates Samsung released
  • 🔄 Is it possible to install a newer version of Android unofficially (and is it worth doing)
  • ⚠️ Risks and limitations when updating an outdated smartphone
  • 🛠️ Step-by-step guide for beginners (if you decide to experiment)

Let us warn you right away: Galaxy S2 has been out of production for a long time, and its hardware capabilities (1 GB RAM, processor Exynos 4210) do not allow you to work comfortably even with Android 7.0. However, for nostalgia or specific tasks (for example, use as a media player or an IoT device), you can still update the firmware.

📊 Are you still using the Samsung Galaxy S2?
Yes, this is my main phone
Yes, but as a spare/for specific tasks
No, but it is lying idle
No, I sold/threw it away a long time ago

Official Android versions for Samsung Galaxy S2 (GT-I9100)

Initially Galaxy S2 went on sale from Android 2.3.3 Gingerbread and proprietary shell TouchWiz 4.0. Samsung released two major updates for this model:

  • 🍯 Android 4.0.3 Ice Cream Sandwich (2012) - the first significant update, which brought a new interface design and improved multitasking.
  • 🍬 Android 4.1.2 Jelly Bean (2013) - the latest official version, which added smooth animations (Project Butter) and expanded notifications.

After Android 4.1.2 support from Samsung stopped. Reasons:

  • 🔋 Insufficient hardware resources (1 GB RAM, single-core processor) for Android 4.4 KitKat and newer.
  • 📉 Falling demand for updates for devices older than 2-3 years (a typical practice of manufacturers of that time).
  • 🔒 Lack of support for new APIs and Google security requirements.
Android version Year of release Features Support status
2.3.3 Gingerbread 2011 Initial firmware, TouchWiz 4.0 ❌ Outdated
4.0.3 Ice Cream Sandwich 2012 New design, improved multitasking ❌ Outdated
4.1.2 Jelly Bean 2013 Project Butter, extended notifications ❌ Latest official

Important: Starting with Android 5.0 Lollipop, Google has tightened the hardware requirements (for example, mandatory support for 64-bit architecture). Galaxy S2 does not meet these requirements.

Unofficial firmware: is it possible to install Android newer than 4.1.2?

Yes, but with serious reservations. Enthusiasts from the community XDA Developers and other platforms have created custom firmware based on:

  • 🍭 Android 5.1 Lollipop (for example, CyanogenMod 12.1) - the most stable option.
  • 🤖 Android 6.0 Marshmallow (projects like LineageOS 13) - works with lags.
  • 🧁 Android 7.1 Nougat (experimental builds) - highly not recommended for everyday use.

Advantages of custom firmware:

  • ✅ More modern interface and functions (for example, permissions for applications in Android 6.0).
  • ✅ Extending the life of the device for specific tasks.
  • ✅ Removing pre-installed software from Samsung (bloatware).

Disadvantages:

  • ⚠️ Performance: even Android 5.1 will slow down on 1 GB of RAM.
  • ⚠️ Battery: outdated battery + unoptimized software = quick drain.
  • ⚠️ Security: lack of security updates from Google.
  • ⚠️ Compatibility: many modern applications (for example, banking) do not work on older versions of Android.
⚠️ Attention: Installing custom firmware requires unlocking the bootloader, which resets the device to factory settings and voids the warranty (if it was still valid). "bricked"?
What is "scaling"?

This is a condition in which the device stops turning on or boots only to the manufacturer's logo. Most often it occurs due to interrupted firmware, incompatible software, or errors when unlocking the bootloader. You can restore operation using special tools (for example, Odin for Samsung), but this requires technical skills.

How to Check Current Android Version on Galaxy S2

If you are not sure which version Android is installed on your Galaxy S2, follow these steps:

  1. Open the menu Settings (icon gears in the main menu).
  2. Scroll down and select About phone (or About device).
  3. Find lines Android version and Build number.

Display example:



Android version: 4.1.2


Build number: JZO54K.I9100XXMS2

If your phone is stuck on the logo or does not turn on, the firmware version can be found through recovery mode (Recovery Mode):

  1. Turn off the device.
  2. Press the buttons simultaneously Volume up + Home + Power.
  3. In the recovery menu, select item Reboot system now (if the phone boots up) or look at the version at the top of the screen.

Turn off the phone before by entering recovery|Use the original USB cable when connecting to a PC|Do not interrupt the menu loading process|Write down the firmware version on paper-->

Step-by-step guide: how to update Galaxy S2 to Android 5.1 (CyanogenMod 12.1)

If you decide to install custom firmware, follow these instructions. You perform all actions at your own peril and risk!

Required tools and files:

  • 🖥️ Computer with Windows (for the app Odin).
  • 🔌 Original USB cable.
  • 📁 Firmware CyanogenMod 12.1 for GT-I9100 (download only from trusted sources, for example XDA Developers).
  • 📁 Google Apps (package gapps for Android 5.1).
  • 📁 File TWRP Recovery for Galaxy S2.
  • 🛠️ app Odin3 (version 3.10.7 or later).

Installation steps:

  1. Unlock bootloader:
    • Enable USB debugging in Settings → For developers.
    • Connect the phone to the PC and run the command in ADB: 
      adb reboot bootloader
  2. Install TWRP Recovery:
    • Run Odin, connect the phone in mode Download Mode (press Volume Down + Home + Power).
    • In Odin select the file TWRP in the field AP and click Start.
  • Flash CyanogenMod:
    • Reboot to TWRP Recovery (press Volume up + Home + Power).
    • Do Wipe → Advanced Wipe (check Dalvik, Cache, System, Data).
    • Install ZIP firmware files and gapps via Install.
    ⚠️ Attention: After installing custom firmware, some functions may not work correctly:
    • 📷 Camera—possible artifacts when shooting video.
    • 🔊 Sound—distortion at high volumes.
    • 📶 Mobile network—problems with 3G/4G (depending on the region).

    Before installation, check reviews of a specific build on the forums.

    💡

    If the phone does not turn on after flashing the firmware, try repeating the steps with a full reset (Factory Reset to TWRP). If the problem persists, revert to the official firmware via Odin.

    Alternative ways to use Galaxy S2 without updating Android

    If updating the firmware seems too risky or difficult, consider alternative uses Galaxy S2:

    1. Media player or photo frame

    • 🎵 Install a lightweight player (for example, VLC) and use the phone to listen to music.
    • 🖼️ Connect to charging and start a photo slideshow via Google Photos (if Android version supported).

    2. Smart home device

    • 🏠 Install Home Assistant or IoT applications to control smart lamps, sockets.
    • 🔌 Use as a control panel for Sonoff or Xiaomi Mi Home (if you find compatible versions of applications).

    3. Game console for retro games. data-i="199">4. Test device for developers

    • 🎮 Install emulators NES, SNES or Game Boy (For example, RetroArch).
    • 🕹️ Connect the gamepad via Bluetooth (if the Android version supports the device).

    4. Test device for developers

    • 💻 If you are learning to app for Android, Galaxy S2 can be used to test applications on weak hardware.
    • 🐞 Helps identify performance and compatibility problems.
    💡

    Even without updating Android, the Galaxy S2 can be useful for highly specialized tasks. The main thing is not to store important data on it and not use it for banking transactions.

    Frequent problems after updating Android on the Galaxy S2 and their solutions

    If you did update the firmware, here are the typical problems and how to fix them:

    Problem Possible cause Solution
    The phone is very slow Lack of RAM for the new version of Android Disable animations in Settings → For developers or return to Android 4.1.2
    Mobile network does not work Lack of drivers for the communication module in custom firmware Install a patch for the modem or return the official firmware
    Battery runs out quickly Outdated battery + unoptimized software Replace the battery or heat it up (use only when connected to the network condition)
    Google services do not work Incompatible version gapps Reinstall the correct package Google Apps for your firmware

    If none of the methods helped, try:

    1. Reset the settings to factory settings (Factory Reset to recovery).
    2. Reflash the device from scratch, following the instructions again.
    3. Seek help on thematic forums (for example, 4PDA or XDA Developers).
    ⚠️ Attention: Details of the firmware process may vary depending on the specific build and version TWRP/Odin. Always check the latest instructions on the forums!

    FAQ: Frequently asked questions about Samsung Galaxy S2 and Android

    Is it possible to install Android 10 or newer on the Galaxy S2?

    Technically, no. The maximum possible version is Android 7.1 Nougat, but it is extremely unstable due to hardware limitations. For comparison: Android 10 requires at least 2 GB of RAM and a 64-bit processor, while Galaxy S2 1 GB RAM and 32-bit architecture.

    Where to download the official firmware for the Galaxy S2?

    Official firmware can be found on the sites:

    • Sammobile (registration required).
    • SamFW (free access).

    Look for files marked GT-I9100 and version 4.1.2 (for example, I9100XXMS2).

    How to return official firmware after custom?

    For this:

    1. Download the official firmware in the format .tar.md5.
    2. Run Odin and connect the phone in the mode Download Mode.
    3. Select the firmware file in the field AP and press Start.
    4. After installation perform a reset via Recovery.

    Warning: this will erase all data from the device!

    Is it worth buying a Galaxy S2 in 2026?

    No if you are looking for a primary smartphone.

    • You need a spare phone for calls/SMS.
    • You collect retro equipment.
    • You plan to use it for narrow tasks (music, IoT, emulators).

    The price of a used one Galaxy S2 in 2026 rarely exceeds 1-2 thousand rubles, but consider the cost of replacing the battery and potential repairs.

    What applications still work on Android 4.1.2?

    The list of compatible applications is shrinking, but some are still available:

    • 📩 Telegram (old versions, for example, 5.13).
    • 🎵 VLC or AIMP for music.
    • 🗺️ OsmAnd or Maps.me for offline maps.
    • 📖 FBReader or Moon+ Reader for books.

    New versions WhatsApp, YouTube or Chrome are not supported. Use web versions through the browser Firefox (if it is still being installed).