The Android system menu is a hidden control area where advanced users can change settings that are not available in the standard interface. Here you can test hardware components, configure a network, restore firmware, or even overclock the device. But such access is fraught with risks: from accidental reset of settings to complete failure of the smartphone.

In this article we will look all legal login methods into system menus of different types: engineering (Engineer Mode), recovery mode (Recovery), as well as hidden settings through ADB and service codes. Let us separately dwell on what actions can void the manufacturer's warranty how to avoid critical mistakes. The information is relevant for devices on Android 8.0–14, but some methods also work on older versions.

We warn you right away: if you are not sure of your actions, it is better to limit yourself to the standard settings. Most tasks (clearing the cache, resetting to factory settings, checking sensors) can be performed without delving into the system menus.

1. Types of system menus on Android: how they differ

By “system menu”, users often mean different things. Let's look at the main types and their purpose:

  • 🔧 Engineering menu (Engineer Mode) is a diagnostic tool for testing hardware components (screen, camera, sensors, communication modules). Available through service codes or special applications.
  • 🔄 Recovery Mode —recovery mode used to reset settings, install firmware, or recover from failures. Included in the standard firmware of all Android devices.
  • 🖥️ ADB Shell —a console for executing commands via Android Debug Bridge. Requires connection to a PC and USB debugging enabled.
  • 🔍 Hidden developer settings — advanced options for debugging (for example, enabling USB Debugging or simulating a secondary display). Activated through the build number.

It is important to understand that not all menus are available on all devices. For example, the engineering menu on smartphones Samsung and Xiaomi differs in structure and service codes. And some manufacturers (like Google Pixel) block some functions in Recovery to protect against unqualified actions.

📊 Why do you need a system menu?
Diagnostics malfunctions
Installing custom firmware
Overclocking/tuning the device
Resetting the password
Other

2. How to enter the engineering menu through service codes

The easiest way is to use USSD service codes. They work on most devices, but may vary depending on the manufacturer and model. Below are the current codes for popular brands:

ManufacturerLogin codeWhat opens
Samsung#0#Display test (colors, sensor)
Xiaomi/Redmi##4636##Test and statistics menu
Huawei/Honor##2846579##Project Menu
Google Pixel##4636##Information about the battery and network
OnePlus*#808#Hardware component test

To use the code:

  1. Open the standard application Phone.
  2. Enter the code as if you were dialing a number (without spaces).
  3. On some devices you will need to press the call button.

If the code does not work, try alternative options for your brand. For example, on Samsung Galaxy also works *#9900# to access system logs.

💡

Service codes do not require root access, but some tests (for example, checking the camera at maximum frequency) may temporarily disrupt the operation of the device. After diagnostics, it is recommended to restart the smartphone.

⚠️ Attention: On devices with Android 12+ some manufacturers block service codes to protect against fraud. If the code does not work, check for firmware updates or use alternative methods (for example, ADB).

3. Entering Recovery Mode: step-by-step guide

Recovery Mode is a separate section of the device memory that starts before the main system boots. It is needed for:

  • 🔄 Resetting to factory settings (Wipe Data/Factory Reset).
  • 📦 Installing official or custom firmware (Apply Update from ADB).
  • 🛠️ Recovering from crashes (Reboot System Now).
  • 🔋 Clearing the cache (Wipe Cache Partition).

To log in Recovery:

☑️ Preparation to enter Recovery Mode

Done: 0 / 4

Button combinations for popular brands:

  • Samsung: Volume up + Power + Bixby (on new models without Bixby - only Volume up + Power).
  • Xiaomi/Redmi/Poco: Volume up + Power (hold for 10–15 seconds).
  • Google Pixel: Volume down + Power, then select from the menu Recovery Mode.
  • OnePlus: Volume down + Power (on some models you need to first turn it off OEM Unlock in the developer settings).

If the device does not respond to the combination, check:

  • Is the battery charged (at least 30%).
  • Is the smartphone connected to the charger (on some models, this blocks the input).
  • Is quick startup enabled (on Samsung it needs to be disabled in the battery settings).
⚠️ Attention: On devices with a locked bootloader (bootloader), an attempt to install custom firmware via Recovery will lead to resetting all data and blocking the device (FRP Lock).

4. ADB commands for accessing system settings

Android Debug Bridge (ADB) is a debugging tool that allows you to execute commands on device from your computer. With it you can:

  • 📱 Launch hidden menus (for example, com.android.settings.Settings$TestingSettingsActivity).
  • 🔧 Change system settings (brightness, animations, screen resolution).
  • 📁 Copy files from a device without root access.

To use ADB:

  1. Enable USB debugging in the developer settings (how to do this - see section 5).
  2. Download Platform Tools from the official website Android Developers.
  3. Connect the device to the PC and run the command in the terminal: 
    adb devices

    (your device should appear in the list).

Examples of useful commands:

  • Open the engineering menu: 
    adb shell am start -n com.android.settings/.TestingSettings
  • Reboot to Recovery: 
    adb reboot recovery
  • Get information about the battery: 
    adb shell dumpsys battery
What to do if ADB does not see the device?

1. Check if the drivers are installed (for Windows, download them from the smartphone manufacturer's website).

2. Try another USB cable (preferably the original one).

3. In the developer settings, enable the option "Cancel USB debugging permission".

4. Restart both the device and the computer.

Beware of commands that change system files (for example adb shell su to get root). to "brick" (breakdown) of the device.

5. How to enable developer settings and hidden options

Menu for. developers contains advanced settings that are not visible to ordinary users:

  • 📱 OEM unlocking (needed to unlock the bootloader).
  • 🔄 Do not turn off the screen (useful for testing).
  • 🎮 Simulate secondary display (for debugging multitasking).
  • 🚀 GPU rendering acceleration (can improve gaming performance).

To activate the menu:

  1. Open Settings → About phone.
  2. Find the item Build number (on Xiaomi this could be MIUI Version).
  3. Click on it 7 times in a row —a notification “You have become a developer!” will appear.
  4. Return to the main settings menu - a new section will appear there For developers.

Some options in this menu may worse performance or break applications. For example, enabling Do not save actions will close all background processes after exiting them.

💡

Does not require developer settings root access, but changes to them may affect system stability. After experiments, it is recommended to reset the settings of this section to the factory settings.

6. Risks and how to avoid them: what can be broken in the system menu

Access to system settings gives greater freedom, but also increases the chances disable the device. Here are the most common errors and their consequences:

ActionRiskHow to avoid
Changing parameters build.prop via ADBCyclic reboot (bootloop)Create a backup copy of the file before editing
Reset via Recovery without backupLosing everyone data (photos, contacts, messages)Use adb backup or cloud services
Unlocking the bootloader on devices with FRP LockLocking your Google account after resettingMake sure that you know the login/password for your account
Changing the battery voltage in the engineering menuRapid discharge or swelling of the batteryDo not change the value if you do not understand the consequences

The most dangerous actions:

  • 🔥 Formatting a partition /system — will make it impossible to boot the OS.
  • 🔌 Disabling critical services (for example, android.process.media) will cause permanent errors.
  • 🔄 Installing incompatible firmware — may “brick” the device (hard brick).

If you still encounter a problem, try:

  1. Boot into Safe Mode (hold the power button and select the appropriate item).
  2. Restore data via Google Account (if backup was enabled).
  3. Contact the service center (save receipts and warranty card).
⚠️ Attention: Manufacturers (for example, Samsung and Xiaomi) track changes in system partitions through Knox or Mi Verify. Even if you restore the device to its original state, traces of interference may remain, which will void the warranty.

7. menu: when it’s not worth taking risks

Before going into the system settings, check if the problem can be solved using standard means:

  • 📊 Diagnostics of hardware problems: Use applications like CPU-Z or Phone Doctor Plus instead of the engineering menu.
  • 🔄 Reset settings: In the standard settings there is an item Restore and reset —it is safer than Recovery.
  • 🔋 Battery optimization: Enable Adaptive battery in the power settings.
  • 📶 Network settings: To change the APN, use Settings → Mobile network.

If you need root access for deep customization, consider alternatives:

  • Magisk - allows you to get root without changing the system partition (systemless root).
  • Shizuku — gives access to ADB commands without connecting to a PC.
  • Tasker — automates tasks without manual intervention in the system.

Remember: 90% of the tasks for which users seek access to the system menu can be solved through the Play Market or standard settings. You should only take risks if you know exactly what you are doing and are ready for the consequences.

FAQ: Frequently asked questions about the Android system menu

❓ Is it possible to enter the system menu without root access?

Yes, most methods (service codes Recovery Mode, ADB) do not require root. However, some actions inside these menus (for example, editing system files) will not be available without superuser rights.

❓ Why does the service code not work on my smartphone?

Possible reasons:

  • Manufacturer blocked the code in the new firmware (relevant for Android 12+).
  • You enter the code not in the standard Phone application, but in instant messengers.
  • The device has custom firmware installed, which removed support for codes.

Try alternative codes for your model or use ADB.

❓ How to exit Recovery Mode if your smartphone is frozen?

If the device does not respond to buttons:

  1. Hold the button Power 10-15 seconds to force a reboot.
  2. If this does not help, remove the battery (if it is removable) for 30 seconds.
  3. For non-removable batteries, wait until they are completely discharged (may take several hours).

If after this the device does not turn on, contact a service center.

❓ Is it possible to roll back the changes made in the system menu?

Depends on the type of changes:

  • If you changed the settings through ADB (for example, animations), return the default values with the command adb shell settings reset.
  • If you edited system files, only flashing will help.
  • If you reset the settings via Recovery, you can only restore the data from a backup.
❓ Is it legal to use the system menu to overclock the processor?

Technically yes, but:

  • This violates the terms of the majority warranty manufacturers.
  • Can lead to overheating and shorten the service life of the chipset.
  • On some devices (for example, Samsung Exynos), overclocking is blocked at the hardware level.

For gaming smartphones (like ASUS ROG Phone or Black Shark) manufacturers themselves provide tools for safe overclocking.