Many smartphone users are thinking about getting the most out of their device, and the idea of running multiple operating systems at the same time seems like an ideal solution. However, unlike on a personal computer, where Dual Boot technology has been standard for many years, on Android mobile devices this process remains a complex and risky task. The concept MultiROM allows you to load different versions of Android or even other OS, such as Ubuntu Touch, on one phone, but requires deep technical knowledge.
It is worth immediately noting that the standard function Settings → About phone does not provide the ability to select a system at startup. Implementation of such functionality is possible only through modification of the bootloader and installation of a special recovery. If you are looking for a way to simply switch between desktops, launcherswill suit you, but to fully change the kernel and file system you will need root access and unlocked bootloader.
It is important to understand that most modern manufacturers block the ability to use third-party bootloaders, which makes installing a second OS impossible on the latest flagships without specific exploits. This material is aimed at enthusiasts who own open architecture devices, such as older models Google Nexus, OnePlus or some smartphones Xiaomifor which the developer community has created the necessary tools.
Technical requirements and hardware compatibility
Before you begin manipulating partitions memory, you need to make sure that your hardware supports multiboot technology. The key component here is not the processor, but a specific implementation recovery (recovery mode). Standard TWRP Recovery by itself cannot manage multiple systems; this requires a modified version of it, known as MultiROM.
Compatibility is limited to specific device models for which the kernel is ported. An attempt to install this manager on an unsupported device will result in the phone turning into a “brick” and no longer turning on. Typically, support is found for devices based on processors MultiROM Manager. An attempt to install this manager on an unsupported device will result in the phone turning into a “brick” and no longer turning on. Devices based on processors usually find support Qualcomm Snapdragon with an unlocked bootloader, but even among them the list is extremely small.
⚠️ Attention: Installing MultiROM requires completely clearing the internal memory. All your photos, contacts and applications will be permanently deleted during the partitioning process.
Having enough free memory is also critical. The second operating system does not take up space in the form of an image file, but creates a full-fledged partition in the data storage structure. For comfortable operation of the second OS, you need to allocate a minimum 16 GB free space, or better 32 GB or more.
Device preparation and backup
The beginning of work should always be accompanied by the creation of a full backup of the current system. Since we will be formatting partitions data and system, any failure may result in loss of access to data. Use tools like Titanium Backup (requires root) or built-in function Backup and restore in TWRP to create a full image (Nandroid backup).
The next step is to unlock the bootloader. This process is different on different devices: for Xiaomi requires waiting for several days after submitting an application in the Mi Unlock service, while on OnePlus this is done through the command fastboot oem unlock. Without completing this step, installing a modified recovery is impossible.
- 📱 Unlock the bootloader via Fastboot mode.
- 💾 Make a full backup of the current firmware to an external drive.
- 🔋 Charge the device to at least 80% to avoid shutdown when flashing.
- 📥 Download images of the main and secondary firmware that are compatible with MultiROM.
After unlocking, you need to install custom recovery. This is done through a computer with ADB and Fastbootinstalled. The command for the firmware is as follows:
fastboot flash recovery twrp-multirom.imgThis version of TWRP contains the code necessary to control the system selection menu at boot. The regular version of TWRP will simply be overwritten or will not see the second system.
Installing the MultiROM manager
After successfully installing the modified recovery, boot into it by holding the button combination Volume Down + Power. In the TWRP menu, go to the Advanced section and select MultiROM. If this item is not there, then you installed the normal version of recovery, and the procedure needs to be repeated.
Inside the MultiROM menu you will be prompted to install the manager itself. This is the basic component that is embedded in the boot sector. The installation process takes a few seconds, after which a reboot is required. The manager works as a layer between the device bootloader and the Android kernel, intercepting control and displaying a selection menu.
If, after installing MultiROM, the phone immediately boots into the main system without a selection menu, go to the MultiROM settings and enable the "Show boot menu" or "Auto-boot delay" option.
It is important to note that installing the manager can change the partition layout on your device. Some versions of MultiROM require reformatting the partition into a file system data to the file system ext4 or f2fs with certain parameters. Ignoring this requirement will result in a cyclic reboot (bootloop).
⚠️ Attention: Some antivirus software on PCs may block ADB drivers or firmware image files, considering them suspicious. Disable protection for the duration of the procedure or add the folder with tools to exceptions.
The process of adding a second operating system
Now that the base is installed, you can add a second OS. In the MultiROM menu, select Add ROM. You will be asked to select the installation source: a firmware image downloaded in advance, or downloading from the Internet (if the function is supported for your device). It is recommended to use a local ZIP archive with the firmware to avoid network errors.
The process of installing a second system is similar to a regular flashing, but with an important difference: the MultiROM installer automatically redirects the files of the new system to a separate directory on the partition data, rather than overwriting the main system. You can install almost any compatible build of Android: LineageOS, Resurrection Remix or even Ubuntu Touchif there is a port.
| System type | Installation complexity | Operation stability | Memory requirements |
|---|---|---|---|
| Android (LineageOS) | Low | High | 10-16 GB |
| Ubuntu Touch | Average | Average | 8-12 GB |
| Sailfish OS | High | Low (on older devices) | 10 GB |
| PostmarketOS | Very high | Test | 4-8 GB |
After selecting the image, the unpacking and installation process will begin. During this time, the screen may go dark or show log files. Never interrupt this process by pressing buttons or unplugging the cableas this will damage the file system of the second OS and it will not boot.
☑️ Second installation checklist OS
Setting up the bootloader and switching between systems
After successful installation of the second system, the MultiROM menu will appear every time you turn on the phone. It allows you to choose which OS to run at the moment. By default, the system will boot in a few seconds unless you press the select button. This time can be configured in the manager settings.
You can designate the Primary ROM, which will boot by default unless you make a manual selection. Switching between systems does not require a reboot into recovery each time; all control occurs at the kernel initialization stage. However, the data on the systems is isolated: applications installed on the first OS are not visible on the second.
Why may the camera not work on the second system?
Often, proprietary camera drivers do not work in secondary systems, since they are strictly tied to the kernel version and main firmware libraries. This can be solved by installing special patches or GApps.
For advanced users, the function of renaming systems in the boot menu is available so as not to be confused between “Android 1” and “Android 2”. This is done through the file manager inside the recovery or special scripts that change the configuration files in the folder /sdcard/multirom/roms/.
Possible problems and ways to solve them
The most common problem is the failure of the second system to boot (bootloop). This often happens due to incompatible kernel versions or driver conflicts. In this case, you need to go into recovery, select the second system in the MultiROM menu and try to clear the cache (Wipe Cache/Dalvik) specifically for it, without affecting the main system.
Another common mistake is the lack of access to the Internet or communication module in the secondary OS. This is due to the fact that the radio module (Baseband) must be compatible with the kernel. Sometimes you need to reflash the modem separately via Fastboot, using the command:
fastboot flash modem NON-HLOS.binIf you accidentally deleted the main system or damaged the bootloader, you can restore the device only through the mode Fastboot or Download Mode (for Samsung), loading the stock firmware. MultiROM is removed through its menu: item Remove ROMs, followed by complete data clearing.
⚠️ Attention: The manufacturer's warranty department will refuse to service a device with broken software if it finds traces of unlocking the bootloader or installing a custom recovery.
MultiROM is a tool for developers and testers, and not for everyday use by the average user due to low stability and complexity of support.
Frequently asked questions (FAQ)
Is it possible to install Windows on Android via MultiROM?
No, the MultiROM project is intended exclusively to run systems based on the Linux kernel (including Android). The Windows ARM or x86 architecture requires emulation or complete replacement of the bootloader, which is not possible within MultiROM. There are projects like Renegade, but they work differently and do not support dual boot.
Will installing a second OS slow down the phone?
The presence of a second system itself does not affect the speed of the active OS, since they are not running at the same time. However, occupied partition space data can reduce space for cache and user files, which indirectly affects performance when memory is full.
Is it safe to use banking applications on a second system?
No, it is not safe. The presence of root access, an unlocked bootloader and a modified recovery violates the integrity of the Android security platform (SafetyNet/Play Integrity). Banking applications will either not start or will work in a limited mode, and your data may be vulnerable.
How to completely remove MultiROM and return to stock?
Go to the MultiROM menu through recovery, select "Remove ROMs" and delete all secondary systems. Then select "Remove MultiROM" to remove the manager. After this, it is recommended to flash the stock recovery and full stock firmware via Fastboot for a complete return to the factory state.