How to find hidden settings on Android: a complete guide with codes and instructions

Android is an open-source operating system, but not all of its features are available through the standard settings menu. Manufacturers and developers often hide advanced features, engineering modes, and debugging tools to prevent accidental changes to settings that could disrupt the device's stability. However, for experienced users, customization enthusiasts, or those who want to get the most out of their smartphone, these hidden settings are a real godsend.

In this article, we will figure out where to look for hidden menus on Android, how to activate them without risking the system, and what opportunities they open up. You will learn about standard access methods through secret codes, the engineering menu, as well as ways to unlock additional functions using ADB and third-party applications. It is important to understand that working with some parameters requires caution - incorrect changes can lead to failures or even bricking of the device. Therefore, before experiments, it is recommended to create a backup copy of the data.

The material will be useful to owners of devices from Samsung, Xiaomi, OnePlus, Google Pixel and other brands, since most methods are universal. However, some codes and menus may differ depending on the Android version and manufacturer's firmware. If you are not sure of your actions, it is better to limit yourself to safe modes, such as checking battery information or testing sensors.

Secret USSD codes for quick access to hidden functions

The easiest way to open hidden Android settings is to use secret USSD codes. These combinations of numbers and symbols act as "passwords" to access service menus, device information, or hardware component tests. Most codes are universal, but some depend on the manufacturer.

To use the code, open the standard application Phone, go to the dialing tab and enter the combination. On some devices, after entering the code, the menu will open automatically, on others you will need to press the call button. If the code does not work, it means that it is not supported by your model or firmware version.

• 📱 General information about the device: ##4636## —displays battery data, usage statistics, network and Wi-Fi information. Useful for diagnosing connection or discharge problems.
• 🔋 Battery and charging test: ##4986*2650468## (for some Samsung) - shows detailed information about the battery status, including the number of charge cycles and actual capacity.
• 📡 Engineering menu for testing the network: ##197328640## — allows you to manually select the network type (2G/3G/4G/5G), check the signal strength and configure the parameters of the communication module.
• 🎵 Audio test: ##0*## —starts testing the speakers, microphone and headphones. Useful if the sound is distorted or disappears.

Some codes may Automatically reset network settings or run tests that temporarily disable communication. For example, the code ##7262626## on devices Google Pixel performs a GPS check, which may take several minutes. Do not interrupt the process to avoid errors in the operation of the module.

⚠️ Attention: Codes starting with #9900# or containing combinations like ##can lead to resetting settings or activating modes that are difficult to cancel. For example, *2767*3855# on some devices Samsung performs a full reset to factory settings without confirmation.

Engineer Mode: advanced diagnostics and configuration

Engineering menu is a powerful tool for diagnostics and fine-tuning settings of smartphone hardware components. It allows you to test the display, cameras, sensors, as well as change network, sound and even processor parameters. However, access to this menu is often hidden, since incorrect changes can lead to unstable operation of the device.

The most common way to open the engineering menu is to use the code ##36446337## (or ##3644633## on some devices). After entering, an interface with tabs will open:

• Hardware Testing — tests of hardware components (sensors, cameras, speakers);
• Location — GPS and geolocation settings;
• Connectivity — network parameters, Wi-Fi, Bluetooth;
• Logs & Debugging — error logs and debugging information.

On devices MediaTek the engineering menu is called MTK Engineer Mode and may require additional rights.

In the menu Hardware Testing you can, for example, check the operation of the gyroscope, accelerometer or proximity sensor. This is useful if the smartphone does not respond to screen rotations or automatically locks during a call. In the Connectivity section, experienced users can manually configure network settings, for example, block certain 4G/5G frequencies if they cause problems with the connection.

⚠️ Attention: Changing parameters in the Band Selection section (selecting network frequencies) may lead to loss of connection if you disable all available bands. To return the default settings, reboot the device or reset the network settings in the standard Android menu.

Check the operation of the sensors (gyroscope, accelerometer)

Test the speakers and microphone

View battery information (voltage, temperature)

Run a camera test (if the image is blurry or with artifacts)

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On devices with processors Qualcomm Snapdragon the engineering menu can be called QC Test Mode and opened with code ##7378423##. Additional options are available here, such as test RF Band (radio frequencies) or setup RRC Version (radio protocol). These parameters are usually used by engineers to debug network equipment, and changing them without understanding the consequences can disrupt the operation of mobile communications.

ADB commands to unlock hidden functions

If secret codes and the engineering menu do not give access to the necessary settings, you can use Android Debug Bridge (ADB) a tool for debugging via a computer. Using ADB, you can activate hidden functions, change system parameters and even unlock options that the manufacturer has disabled in the firmware.

To work with ADB you will need:

1. Enable Developer mode on your smartphone (go to Settings → About phone → Build number and tap on it 7 times).
2. Activate Debugging USB in the developer menu.
3. Install ADB Tools on your computer (available for Windows, macOS and Linux).
4. Connect your smartphone to the PC via USB and confirm permission for debugging.

After this, you can enter commands via the terminal or command line.

Some useful ADB commands to unlock hidden features:

# Enable freeform mode for windowed applications
adb shell settings put global enable_freeform_support 1

Unlock the Developer menu (if it is hidden)
adb shell am start -n com.android.settings/.DevelopmentSettings

Enable network speed display in the status bar (requires root)
adb shell settings put global show_network_speed 1

Activation of the hidden shooting mode (for some cameras)
adb shell setprop persist.camera.HAL3.enabled 1

One of the most popular commands is activation free-form mode (enable_freeform_support). It allows you to run applications in windows of any size, just like on a desktop OS. However, not all applications work correctly in this mode, and some may refuse to open at all.

⚠️ Attention: Commands starting with setpropchange system properties and can lead to unstable operation of the device. For example, incorrect settings persist.camera.HAL3.enabled can damage the camera until the next reboot.

For devices Samsung there is a separate set of commands, since the manufacturer blocks many standard ADB functions. For example, to unlock OEM Unlock (needed to unlock the bootloader), you may need a special utility Samsung USB Driver for Mobile Phones and command:

adb shell
su
setenforce 0
setprop sys.oem_unlock_allowed 1

These commands require rights rootand executing them may void the warranty.

Hidden settings through applications from the manufacturer

Some manufacturers add their own hidden menus that cannot be opened with standard codes. For example, Xiaomi in the firmware MIUI hides advanced settings in the application CIT (Camera Identification Test), and Samsung uses Samsung Members or Samsung Phone INFO for diagnostics.

On devices Xiaomi/Redmi/Poco you can activate hidden functions through the app CIT:

• 🔍 Open the application Camera;
• 📱 Go to the camera settings and tap 5 times on the firmware version;
• 🔧 A menu will appear CITwhere you can test cameras, check autofocus performance and configure shooting parameters that are not available in the standard interface.

This menu also hides options for calibrating sensors and testing the display for broken ones pixels.

Device owners Samsung can use the application Samsung Members to access diagnostic tools:

• 📱 Open Samsung Members;
• 🔍 Go to section Diagnostics;
• 🛠️ Tests of the battery, sensors, speakers, and even checking the authenticity of the device (to identify fakes) are available here.

For deeper diagnostics, you can use the application Phone INFO from Galaxy Store, which shows detailed information about hardware and firmware.

On smartphones OnePlus hidden settings are often accessible through OnePlus Logkit a standard application for collecting logs. To open the extended menu:

• 📱 Run Logkit;
• 🔧 Enter the password 123456 (default);
• 🛠️ A menu will open with sensor tests, network checks and options for debugging.

Here you can also enable diagnostic mode, which records detailed logs of system operation - useful for identifying the causes of random reboots or freezes.

Dangerous hidden settings: what not to do change

Not all hidden settings are harmless. Some parameters directly affect system stability, security or hardware components. Here is a list of changes that can lead to serious problems:

• ⚡ Changing the processor voltage. or GPU (via the engineering menu or kernel) - can cause overheating, sudden shutdowns or even damage to the chip.
• 📶 Disabling the main network frequencies —if you manually block all available bands, the device will lose connection.
• 🔒 IMEI reset or data modification module —will lead to blocking of the network, and it will be difficult to restore IMEI without specialized equipment.
• 🛠️ Changing battery charging parameters (for example, increasing the current) - accelerates battery wear and can cause swelling.
• 🖥️ Disabling system services via ADB (for example pm disable) - some applications are critical for Android operation, and their deactivation will lead to "scorching".

It is especially dangerous to experiment with settings related to unlocking the bootloader or changing the partition EFS (where IMEI and communication module calibration data are stored on devices Samsung partition damage EFS often leads to network loss, and restoration requires contacting a service center.

Another risky partition - kernel settings (kernel). Changing parameters, such as scheduler (task scheduler) or governor (processor frequency regulator), can lead to unstable operation, overheating, or even the inability to boot the system. If you are not sure of the consequences, it is better to limit yourself to safe tests, such as checking the sensors or display.

How to return everything back: resetting hidden settings

If, after experimenting with hidden settings, the device begins to work incorrectly, there are several ways to return everything to its original state. Most temporary changes (for example, activated through ADB or the engineering menu) are reset after a reboot. However, some parameters are saved and require a manual reset.

Ways to roll back changes:

• 🔄 Reboot - helps to reset temporary ones. settings, such as activated free-form mode or changed network settings.
• 📱 Reset network settings —will return the mobile communication, Wi-Fi and Bluetooth settings to factory settings. Path: Settings → System → Reset → Reset network settings.
• 🛠️ Recovery through the engineering menu — in some menus there is an option Restore Defaults (for example, in MTK Engineer Mode).
• 💻 ADB commands to undo changes —for example, to deactivate the free form mode, use:

  adb shell settings delete global enable_freeform_support

If the problem is more serious (for example, a partition is damaged EFS or critical system files have been changed), you may need a full reset to factory settings or flashing via Odin (for Samsung) or Fastboot (for other brands).

On devices with root access you can use applications like BuildProp Editor or Kernel Adiutorto return the changed kernel parameters or system properties. However, this requires understanding exactly what settings were modified. If you are not sure, it is better to reset via recovery:

1. Turn off the device.
2. Press the combination of buttons to enter recovery (usually Power + Volume Up).
3. Select Wipe data/factory reset.
4. Confirm the action and restart the device.

⚠️ Attention: Resetting to factory settings deletes all data from the internal memory, including photos, messages and installed applications. Before the procedure, make sure that important information is saved in the cloud or on external storage.

Hidden settings for specific brands: Samsung, Xiaomi, Google Pixel

Manufacturers often add unique hidden functions that are not available on stock Android. Let's consider the most useful of them for popular brands.

Samsung:

• 📡 Service menu: *#0011# —shows detailed information about the communication module, including signal strength, network type and SIM card status.
• 🔋 Battery test: ##4986*2650468## — displays the actual battery capacity, the number of charging cycles and temperature.
• 🎥 Hidden camera settings: in the application Camera go to settings and tap 3 times on the firmware version - a menu with advanced shooting parameters will open.

On devices Samsung an application is also available Samsung Band Selection (can be downloaded from Galaxy Store), which allows you to manually select network frequencies to improve communication in weak signal.

Xiaomi/Redmi/Poco:

• 🔧 Engineering menu: ##4636## + tab MIUI Version —here you can enable USB debugging without the standard menu for developers.
• 📱 Hidden gestures: in the settings, go to Advanced → Accessibility → Gestures and activate Double tap to wake up (if the option is hidden in your firmware).
• 🔋 Ultra-fast charging mode: on some models you can force-activate fast charging via ADB:

  adb shell setprop persist.sys.fastchg true

The Xiaomi code also works ##6484## for testing sensors and ##64663## for checking the operation of the NFC module.

Google Pixel:

• 📡 Field Test Mode: ##4636## → Phone information —shows detailed data about the network, including the signal level in dBm.
• 🔊 Settings sound: in the engineering menu (##3424##) you can change the equalizer and volume parameters for different scenarios.
• 📱 Hidden animations: in the menu for developers (Settings → System → For developers), activate Window animation, Transition animation i Animation durationto speed up the interface.

On Pixel code also works *#07# for checking test history SAR (radiation level).

FAQ: Frequently asked questions about hidden Android settings

adb shell pm disable-user --user 0 com.miui.analytics