When it comes to mobile operating systems, 99% of users automatically think about Android i iOS. These two platforms have a de facto monopolization of the market, taking together more than 98% of the global share. But what if you need an alternative? Perhaps you're tired of Android's intrusive advertising, Apple's closed ecosystem, or just want to experiment. There are at least 8 full-fledged operating systems for smartphonesthat can become a replacement for the usual giants - and we will analyze each in detail.

In this article you will find not only a description of alternative systems, but also practical advice on installing them, comparing capabilities, as well as answers to key questions: what devices are supported, where to get them firmware, and whether it’s worth trying something new at all. We analyzed both niche solutions for enthusiasts (like PostmarketOS) and commercial platforms (like KaiOS), which are already used by millions of people in developing countries. Ready to dive?

1. KaiOS: Android for feature phones

KaiOS is a hybrid operating system built on the base Firefox OS (which Mozilla closed in 2016). It is aimed at feature phones (push-button phones with limited functions) and cheap smartphones, but at the same time supports modern applications like WhatsApp, YouTube and even Google Assistant. The main advantage is the minimum hardware requirements: the system runs on devices with 256 MB of RAM and processors based on Qualcomm 205.

KaiOS key features:

  • 📱 Support for touch screens and physical keys (depending on models)
  • 🔋 Energy efficiency: battery lasts up to 10 days in standby mode
  • 🌍 Localization in 20+ languages, including Russian (partially)
  • 🛠️ Ability to install applications via KaiStore (similar to Google Play)

Where is it used? The most famous KaiOS devices are Nokia 8110 4G (the famous “banana”), JioPhone (popular in India) and Alcatel Go Flip 3. The system is being actively promoted in Africa and Asia as a budget alternative to Android Go. However, there is a nuance:

⚠️ Attention: KaiOS does not support full multitasking. Applications work on the principle of "one active window", as in older versions of iOS. This limitation is inherent at the kernel level.
📊 Which alternative OS would you try?
KaiOS
Sailfish OS
Ubuntu Touch
PostmarketOS
Another

2. Sailfish OS: Russian footprint in the world of mobile OS

Sailfish OS is a Finnish development of a company Jollathat positions itself as “an independent alternative to Android and iOS.” The system is built on the basis of an open project Mer (fork Meego, which was once developed by Nokia and Intel). Interesting fact: Sailfish OS is certified in Russia as domestic software and is used in some government projects (for example, in smartphones Aurora).

What Sailfish OS can do:

  • 🐧 Full support for Android applications through a compatible layer (but not all work correctly)
  • 🔒 Built-in tools for data encryption and privacy protection
  • 🎨 Unique interface with gestures (for example, swipe from the edge to go back)
  • 📱 Official support for devices: Sony Xperia 10/10 II/10 III, Fairphone 4, as well as Chinese smartphones Unisoc

How to install? For supported models there are official firmware on the Jolla website (license cost is about 50 €). For other devices you will have to use unofficial ports from the community, but there are risks:

⚠️ Attention: Unofficial builds of Sailfish OS may not support communication modules (4G, Wi-Fi) or cameras Before installing, check the list of compatible hardware on the forum. Together.Jolla.com.

Example of supported devices:

ModelProcessorSupport statusLicense price
Sony Xperia 10 IIISnapdragon 690Official49.90€
Fairphone 4Snapdragon 750GOfficial49.90€
Xiaomi Mi A2Snapdragon 660CommunityFree
OnePlus 6/6TSnapdragon 845CommunityFree
💡

If you want test Sailfish OS before purchasing a license, you can install it on the emulator via VirtualBox or QEMU. The official image for emulation is available on the Jolla website.

3. Ubuntu Touch: Linux on your smartphone

Ubuntu Touch is a mobile version of the famous Linux system, developed by the foundation UBportsThe project started in 2013 as a Canonical initiative, but after its closure it was transferred to the community. Today, Ubuntu Touch is the only OS that offers Linux stack on a smartphone, including support apt for installing packages.

Key features:

  • 🐧 Full integration with desktop Ubuntu: you can connect your smartphone to the monitor and use it as a PC (Convergence)
  • 🔒 No tracking and data collection (unlike Android)
  • 📦 Support Liberty —a compatible layer for running Android applications (analogue Anbox)
  • 📱 Officially supported: Google Pixel 3a, Fairphone 3/4, OnePlus One, Volla Phone

How to install? The process depends on the device. For officially supported models there are instructions on the website UBports. For example, for Google Pixel 3a you will need:

  1. Unlock the bootloader (fastboot oem unlock)
  2. Install TWRP or another custom recovery
  3. Flash the Ubuntu Touch image via adb sideload
⚠️ Attention: On some devices (for example, OnePlus 6) Ubuntu Touch does not support the NFC module and a two-level camera. Before installation, check the list of known bugs for your model.
How to enable Convergence mode?

To activate the "smartphone as" mode PC" connect the device to the monitor via USB-C → HDMI adapter. The system will automatically switch to the desktop interface with support for mouse and keyboard. In this mode, you can run full-fledged Linux applications, for example LibreOffice or GIMP.

4. PostmarketOS: Linux for enthusiasts

PostmarketOS (pmOS) is an ultra-light operating system based on Alpine Linux, designed to extend the life of old smartphones. The project positions itself as a “10-year smartphone”: the goal is to provide support for devices for ten years after their release. The system weighs only ~150 MB and can even work on devices with 512 MB RAM.

PostmarketOS Features:

  • 🐧 Full Linux with support apk (Alpine package manager)
  • 🔧 Modular architecture: you can choose a graphical shell (Phosh, Plasma Mobile, Sxmo)
  • 📱 Even ancient devices are supported: Nexus 5 (2013), Samsung Galaxy S3 (2012), HTC One M7 (2013)
  • 🛠️ No official support for Android applications (but you can install Waydroid manually)

Installing pmOS requires skills in working with a terminal. Example commands for firmware on Samsung Galaxy S3:

# Installing pmOS via pmbootstrap

pmbootstrap init


pmbootstrap install --android-recovery-zip


pmbootstrap flasher flash_rootfs

The main disadvantage is the lack of out-of-the-box support for proprietary drivers (for example, for a camera module or GPS). data-i="132">PostmarketOS is the best choice for reviving old smartphones, but requires deep knowledge of Linux. If you need a “just working” phone, consider other options.

💡

PostmarketOS is the best choice for reviving old smartphones, but requires deep knowledge of Linux. If you want a phone that "just works", consider other options.

5. LineageOS: custom Android without Google

LineageOS is not exactly an alternative to Android, but rather a “cleaned up” version of it without proprietary Google services. famous CyanogenMod and offers users complete control over the system. The main advantage is lack of bloatware (pre-installed applications) and the ability to choose: install Google Apps or do without them.

Why LineageOS popular:

  • 📱 Supports more than 200 devices (from Samsung Galaxy S5 to Xiaomi Redmi Note 7)
  • 🔒 Regular security updates (weekly builds for most devices)
  • 🛠️ Ability to install micro-G (Google alternatives Play Services)
  • 🎨 Support for themes and interface customization

How to install? The process is standard for custom firmware:

  1. Unlock bootloader (fastboot flashing unlock)
  2. Install TWRP or OrangeFox Recovery
  3. Flash LineageOS and (optional) Open GAPPS

Important nuance: without Google Apps many applications (for example, banking) may not work. In this case, you will have to use alternatives like MicroG or F-Droid.

Unlock the bootloader|Make a data backup|Download the firmware for your model|Check the compatibility of modules (Wi-Fi, camera)|Install a custom recovery-->

6. HarmonyOS: China's answer to Android

HarmonyOS (or Hongmeng OS) is an operating system from Huaweideveloped as a replacement for Android after US sanctions. Despite the fact that the system is positioned as “universal” (for IoT, smartphones, TVs), its mobile version is in many ways similar to Android: it supports APK files and has a similar interface. However, under the hood, HarmonyOS uses its own kernel (LiteOS) and does not depend on Google services.

Key features:

  • 📱 Works only on Huawei devices (starting from Mate 30 i P40)
  • 🔄 Support for cross-platform applications (one software for smartphone, tablet and smart watch)
  • 🛡️ Enhanced data protection (according to Huawei, the system is “untraceable”)
  • 🌍 Officially localized in Russian, but the app store AppGallery poorer than Google Play

Is it possible to install HarmonyOS on other smartphones? Technically yes, but only through unofficial ports (for example, the project OpenHarmonyHowever, there are critical limitations:

⚠️ Attention: Unofficial builds of HarmonyOS do not support Huawei services. (for example, Huawei Mobile Services), which makes many functions useless. In addition, the system is optimized for processors Kirin, on Snapdragon there may be performance problems.

Example of devices with HarmonyOS:

ModelProcessorHarmonyOS version
Huawei Mate 50 ProKirin 9000S3.0
Huawei P60 ProKirin 90003.1
Huawei Watch 3Kirin A12.0
Huawei MatePad 11Snapdragon 8653.0

7. Niche OS: Tizen, Plasma Mobile and others

In addition to the listed systems, there are and more exotic options that are not suitable for everyone. Let's consider the three most interesting:

Tizen OS (from Samsung):

  • Used in smart watches Galaxy Watch and Samsung TVs, but there are also versions for smartphones (for example, Samsung Z1-Z4)
  • Supports applications on HTML5, but the ecosystem is extremely limited
  • The last smartphone on Tizen (Samsung Z4) was released in 2017 - the project is actually frozen

Plasma Mobile (from KDE):

  • Graphical shell for Linux systems (for example PostmarketOS or Manjaro)
  • Uses KDE Plasma the same interface as on desktop Linux distributions
  • Supports Flatpak for installing applications, but optimization for mobile screens remains much to be desired

Replicant (free Android):

  • 100% open version of Android without proprietary drivers
  • Supports a limited list of devices: Samsung Galaxy S2/S3, Google Nexus 4/5
  • Due to the lack of proprietary libraries, the following may not work: GPS, camera, 3G/4G

These systems are suitable only for enthusiasts who are willing to put up with the lack of many functions. They are practically unsuitable for everyday use.

8. How to choose an alternative OS: checklist

Before installing an alternative system, answer a few questions:

  1. What is your goal?
    • 🔒 Confidentiality → Ubuntu Touch, Replicant
    • 📱 Extending the life of an old smartphone → PostmarketOS, LineageOS
    • 💼 Corporate use → Sailfish OS (certified in the Russian Federation)
    • 💰 Budget solution → KaiOS
  • What device do you have? Check the list of supported models on the official project websites.
  • Are you ready for restrictions? Most alternative OS do not support banking applications, Netflix, games and other services linked to Google Services.
  • Are you skills? Installing custom firmware requires knowledge of commands fastboot, adb and working with recovery.

    • If you are a beginner, start with LineageOS this is the easiest way to get acquainted with alternative systems. You can use a secondary device for experiments.

    💡

    Before installing any alternative OS, make a complete backup of your data via TWRP or adb backup. Recovery from unsuccessful firmware may require flashing the stock firmware via EDL mode.

    FAQ: Frequently asked questions about alternative OS

    Can I install Windows on a smartphone?

    Technically yes, but with reservations. There is a project WoA (Windows on ARM) that allows you to run Windows 11 on smartphones with processors Snapdragon 8cx or Microsoft SQ1/SQ2 (for example, Surface DuoHowever:

    • 🖥️ This is not a mobile OS, but a full-fledged Windows with an adapted interface.
    • 🔋 Autonomy drops 2-3 times due to high power consumption.
    • 📱 Touch input works clumsily - for comfortable work you need a keyboard and mouse.

    For most users, this solution is not practical.

    Will banking applications work on alternative OSs?

    Most likely not. Banking applications (Sberbank, Tinkoff, VTB) require Google Play Services or certified. Android devices. Exceptions:

    • 🏦 Sailfish OS with installed Alien Dalvik (not all banks work).
    • 🏦 LineageOS with MicroG (partial support, problems with Push notifications are possible).

    The best option is to use web versions of banks or a separate device on stock Android.

    Is it possible to return the original firmware after installing an alternative OS?

    Yes, in most cases. To do this you need:

    1. Find the stock firmware for your model (usually on the forums XDA-Developers or 4PDA).
    2. Flash it using fastboot or special utilities (for example, Odin for Samsung).
    3. Restore data from a backup (if one was made).

    An exception is devices with a locked bootloader (for example, some models Xiaomi or HuaweiIn this case, official unlocking through the manufacturer may be required.

    Which alternative OS is the most stable?

    In terms of stability and functionality leads LineageOS. It:

    • 📱 Supports the maximum number of devices.
    • 🔄 Receives regular security updates.
    • 🛠️ Has a minimal number of critical bugs (compared to PostmarketOS or Ubuntu Touch).

    If you need a system “for everyday use” and not for experiments, this is the best choice among the alternatives.

    Where to download firmware for alternative OS?

    Official sources:

    • 🌍 KaiOS —only for supported ones devices.
    • 🇫🇮 Sailfish OS —paid licenses for official devices.
    • 📦 Ubuntu Touch —free images for supported models.
    • 🤖 LineageOS —weekly builds.

    Look for unofficial firmware and ports at:

    • XDA-Developers (section Original Development)
    • 4PDA (forums on device models)
    • GitHub (repositories of projects like PostmarketOS)
    ⚠️ Attention: Download firmware only from trusted sources. Fake images with malware are common on the Internet (especially for popular models like Xiaomi Redmi Note).