How to edit system files on Android

Deep customization of the operating system Android opens up opportunities for the user that are not available in the standard operating mode. Editing system files allows you to remove pre-installed software, change fonts, optimize processor performance, and even completely transform the visual style of the interface. However, interfering with the directory structure /system or /vendor requires high qualifications and understanding of the OS architecture.

Any change in configuration files carries the risk of turning the device into a “brick”. Android's security system by default blocks access to critical sections of memory for regular applications. To bypass these restrictions, you must obtain advanced access rights. In this article, we will examine in detail the tools and methods for safely editing system data.

Preparing the device and obtaining superuser rights

Before you start modifying files, you need to unlock the bootloader and install root access. Without these steps, any attempt to write to the system partition will be rejected by the system kernel. The process of obtaining root access varies depending on the device model and firmware version.

The most common method is to use the utility Magisk. This tool allows you to implement superuser rights into the boot image without changing the system partition (systemless root), which improves stability. After installing Magisk, an application for managing access rights appears in the system.

⚠️ Attention: Unlocking the bootloader on many smartphones (for example, Huawei or some Samsung models) can lead to irreversible blocking of camera functions or triggering Knox protection.

An alternative way to access files without full root is to use debugging software. ADB (Android Debug Bridge). This method allows you to make changes to certain configuration files through the computer, but access to critical kernel files will still be limited without root access.

Required tools for working with files

For effective editing of system data, a standard file manager is not enough. You will need specialized applications that can work with superuser rights and mount partitions in write mode. Choosing the right software is critical to maintaining data integrity.

One ​​of the best solutions is MT Manager or Root Explorer. These applications provide an easy-to-use interface for navigating hidden directories, a built-in HEX editor, and the ability to create backups before making changes. They automatically request root access upon startup.

• 🛠️ File managers with root: Allow you to move, delete and edit files in folders /system, /data and /vendor.
• 💻 ADB and Fastboot: Command line tools for transferring files and executing scripts with computer.
• 📝 Text editors: Specialized utilities (for example, QuickEdit Pro) for editing XML and configuration files without breaking the encoding.

When working through a computer it is also useful to use app Android Studio or minimalistic sets Platform Tools. They provide a stable USB connection and allow you to execute complex automation scripts.

Mounting partitions in write mode

By default, the Android system partition is mounted in read-only mode (ro). This is a fundamental security measure. To make changes, you need to remount the partition to read-write mode (rw). An error at this stage will result in the file simply not being saved.

Modern file managers, such as MT Manager, often perform this operation automatically when trying to edit. However, in some cases, especially on devices with a file system EROFS or newer versions of Android, manual intervention through the terminal is required.

adb shell
su
mount -o rw,remount /system

If the command is successful, you get full control over the files. After completing all operations, it is strongly recommended to return the partition to its original state to avoid accidental data corruption by other processes.

Command	Description of action	Required rights
mount -o ro,remount /system	Return to read mode	Root
chmod 644 file	Changing file access rights	Root
chown root:root file	Changing file owner	Root
ls -l /system	Viewing a list of files and rights	Basic

Editing configuration files and libraries

The bulk of Android settings are stored in files of the format XML, prop i db (databases). Changing these files allows you to fine-tune the behavior of the system, from screen timeout to network settings.

For example, the file build.prop contains many parameters that determine the identity of the device and its capabilities. Editing this file requires special care: one extra line or wrong character can lead to a cyclic reboot (bootloop).

When editing files, it is important to respect the encoding. Most system files use encoding UTF-8 without BOM. Saving the file in a different encoding (for example, UTF-16) will make it unreadable for the system, which will cause errors when loading the corresponding services.

⚠️ Attention: Never change the size of fonts or icons in system resource files (resources.arsc) without first decompiling and rebuilding using special tools.

To edit databases .db (for example, settings of a telecom operator or alarm clocks), it is better to use specialized SQLite editors, available in the same advanced file managers. Direct editing of database binary code with a text editor is unacceptable.

What is SELinux and how does it affect editing?

SELinux (Security-Enhanced Linux) is a kernel security module that can block access to files even with root access. In Enforcing mode, the system strictly controls processes. For deep modification, it is sometimes necessary to switch the mode to Permissive through the setenforce 0 commands, but this reduces the overall security of the device.

Removing system applications (Bloatware)

One ​​of the most common reasons for editing system files is to remove pre-installed garbage that cannot be uninstalled using standard means. These applications take up space in the /system/app or /system/priv-app.

section. Simply deleting the application folder can break system dependencies. A safer method is to rename the file .apk (for example, adding a suffix .bak) or move it to another folder. This allows you to test the system without the application and easily restore it in case of failure.

• 🗑️ Secure deletion: Rename the APK file instead of completely erasing it.
• 🔄 Recovery: Return the original file name if problems arise.
• 🚫 Prohibited actions: Removing system frameworks and Google Play Services without a deep understanding of their role.

There are automated scripts and Magisk modules for removing bloatware. They are often preferable to manual editing, since they take into account the relationships between system components and create rollback points.

Restoring the system after editing errors

Even experienced users are not immune from errors. If after editing the files your smartphone stops loading, there is no need to panic. There are several scenarios for restoring the device's functionality.

If the device boots but is unstable, first check the logs via logcat. This will help identify which file or service is causing the problem. Often it is enough to return the changed file from the backup copy.

In case of bootloop (cyclic reboot), you will need access to the Recovery mode. If you have custom recovery installed (TWRP, OrangeFox), you can connect your phone to your computer in MTP mode and replace damaged files in the System section through the recovery file manager.

⚠️ Attention: If you did not create a backup before editing, the only recovery method may be to completely flash the device via Fastboot or Odin mode, which will lead to the loss of all user data.

For critical errors, when the device does not respond to buttons, the mode may be required EDL (Emergency Download Mode) or using manufacturer-specific tools to restore the factory image.

Is it possible to edit system files without root access?

Full editing of files in section /system without root access is impossible due to limitations of the Linux kernel. However, using ADB, you can change some settings through commands settings put or pm disable, which affects the behavior of the system, but does not change the firmware files themselves.

What to do if the phone goes into an endless reboot?

Try to boot into Recovery mode. If you have a backup, restore it. If not, try deleting or renaming the last modified file through the recovery file manager (if connected to a PC). In extreme cases, only flashing will help.

Is it safe to change the build.prop file?

Changing build.prop is considered one of the riskiest actions. A syntax error or incompatible parameter value is almost guaranteed to cause the system to fail to boot. Do this only if absolutely necessary and always have a backup copy on hand.

How to find out which file is responsible for what?

Use an Internet search for the file name and model of your device. Developer forums (XDA Developers) and specialized chats in instant messengers are the best sources of information about the purpose of specific system files and libraries.