Working with system images Android often becomes a necessity for enthusiasts involved in modifying the operating system or restoring devices after unsuccessful experiments. Files with the extension .img are sector-by-sector copies of memory sections containing the file system, bootloader or kernel. Such files cannot be opened by normal operating system tools Windows or Linux as they are not standard archives or documents.
To interact with this data, specialized utilities are required that can mount images as virtual disks or extract their contents directly. The choice of a specific tool depends on your goal: do you want to simply view a list of files, replace the boot logo, or completely rebuild the firmware for a custom build. Understanding the structure of the image is critically important before starting any manipulations.
In this material we will look in detail at how to open the firmware Android in format img, we will consider the best apps for working with them and warn against typical errors that can turn the device into a “brick”. We will pay special attention to the differences between images system.img, boot.img and recovery.img, since the methods of working with them are significantly different.
Image file structure and partition types
Before choosing a tool, you need to understand what type of image you are dealing with. Firmware Android rarely consists of one file; usually this is a set of images for different sections of the device’s memory. The most common is system.img, which contains the operating system itself, applications and libraries. This partition most often uses the file system ext4 or f2fs, which allows you to mount it like a regular disk if you have the appropriate software.
Another important type is boot.img. This file contains the Linux kernel (kernel) and the startup disk (ramdisk) required to boot the system. Unlike a system image, boot.img has a specific header structure and is not a direct copy of the file system. To edit it, you need tools that can unpack and repack this particular format, and not just mount it.
There are also recovery recovery.img and bootloader images bootloader.img. They perform official functions and require careful handling. Changing the contents of these files without in-depth knowledge may make it impossible to turn on the device. Modern devices also use a format Super Imagethat combines several logical partitions into one physical one, which complicates the process of retrieving data using traditional methods.
⚠️ Attention: Never try to mount or edit a partition
bootloaderormodemregular file managers. This is service binary data, changing which is almost guaranteed to damage the device.
apps for viewing and editing on a PC
For users who prefer a graphical interface, there are a number of powerful utilities that allow you to work with disk images. The most universal solution for the environment Windows is the app WinImage. It allows you to open files .img, view their structure, extract files and even add new ones, automatically recalculating the size of the image when saving.
Another popular tool is OSFMount. This utility specializes in mounting disk images as virtual drives on the system. Once mounted, you access the image files through My Computer, just as if you had inserted a USB flash drive. This is extremely convenient for quickly copying resources or logs without the need to use the command line.
For deeper editing, especially working with the file system ext4, professionals often use Linux File Systems for Windows from the company Paragon. This driver provides full support for reading and writing Linux partitions in a Windows environment. However, it is worth remembering that direct writing to a mounted system image may violate file access rights (permissions), which will lead to errors when loading Android.
Usage command line and Android Image Kitchen utilities
If graphical utilities cannot cope with the task or you need to work with specific compression formats, console tools come to the rescue. The gold standard for unpacking and assembling images boot.img i recovery.img is the utility Android Image Kitchen. It automates the process of extracting the kernel and ramdisk, allowing you to modify their contents and assemble them back without losing headers.
To work with file systems ext4 on the Linux command line or through the environment Cygwin on Windows, the utilities tune2fs, e2fsck and resize2fs. They allow you to check the integrity of the image, resize it and mount it through the device loop. For example, to mount an image, you can use the command:
sudo mount -o loop system.img /mnt/androidAfter executing this command, the contents of the image will become available in the directory /mnt/android. This gives complete control over files, allowing you to replace system applications or edit configuration files. However, after making changes, the image must be correctly unmounted with the command umountso that the data is correctly written to disk.
Always create a backup copy of the original .img file before any editing. Name the copy, adding the suffix _backup, so that in case of an error you can quickly roll back.
Mobile applications for working with images
Sometimes there is a need to open or mount an image img directly on a smartphone, without using a computer. For this, there are applications that require root access. One of these solutions is DiskMount or specialized file managers with support for mounting images, such as advanced versions of MT Manager.
These applications use the capabilities of the Linux kernel, on which Android is based, to mount the image as a loop device. Once mounted, you can move files between the phone's internal memory and the image content. This is convenient for quickly replacing themes, fonts or system icons directly on the device.
However, mobile methods have limitations. Mobile processors may be slower to process operations on large images, and the risk of accidental corruption of system files is higher due to the limited interface. In addition, not all phones support mounting certain types of file systems without rebuilding the kernel.
☑️ Preparing to edit the image
Compatibility table of tools and formats
The choice of the right tool depends on the type of image and your operating system. Below is a summary table that will help you navigate the variety of available software.
| File type | File system | Recommended tool (Windows) | Recommended tool (Linux) |
|---|---|---|---|
system.img |
ext4 / f2fs | Linux File Systems (Paragon) | mount -o loop |
boot.img |
Specific header | Android Image Kitchen | MagiskBoot / unpackbootimg |
userdata.img |
ext4 | WinImage (view only) | e2fsprogs |
super.img |
LPA (Logical Partition) | LPunpack | lpunpack |
As can be seen from the table, there is no universal solution for all file types. The image super.imgthat appeared in devices with the project Project Treblewill require special unpacking utilities, since it contains several nested images. An attempt to open such a file with a regular archiver will result in an error.
⚠️ Attention: Firmware formats are constantly updated by manufacturers. What worked for Android 10 may not work for Android 14. Always check the documentation for a specific utility to see if it supports new versions of Android.
Converting and extracting data from archives
Often firmware is not distributed in its pure form .img, but as part of archives .zip or specific update packages .ozip, .payload.bin. In such cases, the first step is to extract the image itself. For files payload.binused in OTA updates from Google and many vendors, a utility is required. payload_dumper.
This app analyzes the update binary file and extracts individual partition images from it (system, vendor, product). The process may take a long time depending on the file size and disk speed. After a successful dump, you receive standard .img files that you can work with using the methods described above.
To convert images to other formats, for example, for emulation in QEMU or VirtualBox, you may need conversion utilities like qemu-img. It allows you to convert a raw image into qcow2 or vdiformat, changing the disk size and compression type if necessary. This is useful for testing Android x86 builds on a personal computer.
What to do if the image is damaged?
If the utility reports a checksum error or header corruption, try using the e2fsck utility to repair the file system. Enter the command 'e2fsck -f file.img' in the terminal. If this does not help, the file is most likely not fully or partially downloaded, and you will have to download it again.
Precautions and common mistakes
The main mistake newbies make is trying to write the modified image back to the device without checking its size. Memory sections on smartphones have a fixed size. If your new one turns out to be even one byte larger than the original one, the firmware process will be interrupted, or, worse, the data will be written over the adjacent partition, destroying the bootloader. system.img turns out to be at least one byte larger than the original one, the firmware process will be interrupted, or, worse, the data will be written over the adjacent partition, destroying the bootloader.
Always check the file size before flashing. Use command ls -l in the terminal or file properties in Windows to compare. It is also critical to respect access rights (chmod) and file ownership (chown) when replacing system elements. Incorrect permissions can lead to a cyclic reboot (bootloop), since the system will not be able to start critical services.
Another common problem is incompatibility of kernel versions. If you replace modules in system.img, make sure they are compatible with the kernel version in your boot.img. Mixing components from different versions of Android or different builds without understanding the dependencies is a sure way to end up with a broken device.
Safely working with images requires strict adherence to partition sizes and file access rights. Any deviation from the original structure may make the device unbootable.
Frequently asked questions (FAQ)
Is it possible to open an .img file with a regular archiver like WinRAR?
In most cases, no. Files .img are not archives, but sector-by-sector copies of disks. Archivers do not understand the structure of the ext4 file system or the headers of boot images. However, some images may have an extension .img.gz or .img.zip —in this case, you first need to unpack the archive to get a clean .img file.
Is it safe to mount system.img on Windows to replace applications?
This is risky. Windows ext4 filesystem drivers (such as those from Paragon or Ext2Fsd) may not handle Linux permissions (SELinux context, permissions) correctly. After writing files from Windows and flashing the firmware back, the Android system may refuse to start due to security violations. It is recommended to use Linux or emulators for such tasks.
What is the difference between fastboot flash and writing an image via Recovery?
The command fastboot flash writes the image directly to the memory partition, bypassing the recovery file system. It's faster and more reliable for system partitions. Recovery mode is usually used to install updates in .zipformat, which contain installation scripts. Direct writing .img to Recovery is not possible in all custom recovery (for example, TWRP supports this through the "Install Image" function).
How can I find out what type of file system I have in the image?
On Linux you can use the utility file or blkid. Enter file system.imgin the terminal, and the system will prompt you for the type (for example, "Linux rev 1.0 ext4 filesystem data"). On Windows, this information can be shown by advanced disk managers or Hex editors based on signatures at the beginning of the file.
What is Super Image and how to work with it?
Super Image is a container introduced in Android 10 for dynamic partition management. It combines system, product, vendor and other sections. To access the data inside, you must first unpack it using the utility lpunpack into separate images .img, and only then work with them using standard methods.