We are all familiar with the rich settings of Android devices - each smartphone or tablet can be customized by activating or disabling certain functions, adjusting certain parameters. But few people suspect the existence of such a thing as the Android engineering menu. It is hidden from view because to a simple user there's not much to do here. But if you are an experienced user or want to gain experience in fine-tuning the device and operating system, then this menu will be useful to you.

Let's figure out why we need an engineering menu in a smartphone? The answer is simple - for very fine tuning of the device. For example, increasing the volume on Android is only possible through the engineering menu. Here you need to visit the audio settings item and play with the presented parameters. Here it is possible to manually adjust the sound volume in various modes and at various volume levels.

Let's look at an example:

• You find that your smartphone's speaker starts to wheeze at maximum volume;
• We go to the engineering menu using one or another command;
• Go to the audio settings and change the volume in the specified mode and in the specified gradation;
• We exit the engineering menu and check the results - the volume should decrease.

Is it possible to make such fine adjustments only through the standard setup menu? Naturally, there is nothing of the kind here.

Here you can adjust the sound in the headphones, adjust the sensitivity of the microphone, and perform other actions with the sound. Before getting into the settings, you need to find detailed instructions that will help you make the adjustments as correctly as possible, without the risk of damaging the speakers with a microphone or completely depriving your smartphone/tablet of your voice.

What other functions are there in the engineering menu? Examination network modules, adjusting the reception range, setting up an auto-answer, testing the modem, setting up connections with other devices, setting up the receiver, testing the camera, sensor, screen, battery and other modules.

Separately hidden menu geolocation settings added– here you can check the functionality of the GPS chip, enable/disable A-GPS, and check other settings. It is also possible to adjust fonts, play with USB settings and perform other actions.

Please note that the service menu on Android is intended for professionals who are aware of their actions. If you came here out of idle curiosity, try not to touch parameters you don’t understand and don’t rearrange the settings sliders.

How to enter the engineering menu on Android

Entering the engineering menu on Android is most often done using special commands, similar to the most common USSD commands. The difference is that you don’t need to press the call button at the end - after typing the command, it will automatically transfer to the specified menu. The universal code for the engineering menu on Android is *#*#3646633#*#*. It works on many phones and allows you to instantly enter service settings.

Some smartphones and tablets do not respond to the above command. So you can try the following options:

• *#*#4636#*#*;
• *#15963#*;
• *#8255#*;
• *#*#7378423#*#* (for Sony smartphones);
• *#*#3424#*#* (code for HTC smartphones);
• *#*#2846579#*#* (code for Huawei smartphones).

You can enter the engineering menu on Android immediately after entering the command. There is no dependence on the operating system version - the codes are valid for Android 2.2, Android 4.4 and other versions of Android OS. If the code does not fit, you should look for other combinations.

Some commands lead not to the service menu, but to the testing menu - it allows you to check the screen, sound, wireless modules, microphone and much more. Menus for testing can be English or Russified.

Some manufacturers deprive smartphones and tablets of access to the engineering menu, replacing it with numerous commands for testing modules or configuring certain parameters. For example, this is what Samsung does - many new models do not have a single service menu. Information about available service teams can be found on specialized resources and on the websites of service centers.

To access the engineering menu you can use special applications . A typical example is the Mobileuncle MTK Tools application. It will allow you to gain separate access to device settings and operating system settings. The application is really convenient, but it has a drawback - it only works on devices with MTK processors.

If your smartphone/tablet runs on a different platform, you can try looking for alternative applications to access the engineering menu on Android.

Setting up Android through the engineering menu is associated with certain risks. For example, beginners always have the opportunity to accidentally disable this or that functionality. When understanding the purpose of certain items, you need to familiarize yourself with the appropriate instructions. Otherwise, equipment failure may occur. If you are afraid of damaging or breaking something, do a complete backup copy your device - in case of a fatal error, you can perform Hard Reset and restore your smartphone or tablet.

Never enter commands whose purpose you do not know. The thing is that some of them are designed to quickly change critical system parameters or perform a general reset. Moreover, some commands perform a general reset without confirmation, instantly erasing all contents.

Engineering menu on Android devices, this is a special “built-in” application into the operating system that allows you to fine-tune the device. This is necessary to debug the operation of the hardware and, of course, software. But often users want to change some settings at their own discretion. In this case, the question arises of how to enter the Android engineering menu. This can be done using special service codes or third-party software.

What options does the engineering menu have?

Settings and menu design on Android devices may vary depending on the phone manufacturer. In general, users resort to using the engineering menu for the following reasons:

• Setting up audio on the phone (ringer volume, interlocutor’s voice during a conversation);
• Changing camera settings;
• Using recovery mode;
• Setting microphone sensitivity;
• Disabling unused frequencies to save phone battery;
• Obtaining information about the device's MAC address;
• Setting up Bluetooth and Wi-Fi.

The Android engineering menu provides the user with almost limitless possibilities. But you should always remember that only advanced users can use it. Changing some settings may cause incorrect operation smartphone or tablet. If you don't know what each menu item directly does, simply leave it alone.

The developer mode includes setting up Hardware Testing equipment and also contains the following items:

• Audio – volume control in the phone speakers.
• Camera – allows you to configure various camera parameters (image size, type, etc.).
• Diving current camera shows the current of the camera.
• CPU Stress Test performs a test load on the central processor.
• De-sense is a device manager that manages configuration parameters.
• Display – setting the frequency of the outgoing signal.
• IO – setting up input/output operations.
• Memory – key information about memory.
• Power – information about the battery.
• SD Card Test - testing a memory card.
• TouchScreen – setting up the touch screen, checking sensitivity.
• USB - testing operation USB port on your phone.

In the Connectivity tab you can get information about devices that work with the outside world. These include Bluetooth, Wi-Fi and FM module. The Log and Debugging tab allows you to view the battery log, set the debugger level and run a special MTK log. In the Others tab you can change fonts, as well as view the temperature of the processor and battery.

How to enter the engineering menu: using code combinations

To enter the engineering menu as quickly and easily as possible, you will need special engineering codes. Each manufacturer has its own combination, which opens access to the engineering menu in Android.

To enter the menu you need to:

In most cases, this technique allows you to open the service menu. Below are some combinations for the most popular phones:

• Models from HTC - *#*#3424#*#*, *#*#4636#*#* or *#*#8255#*#*;
• Samsung devices - *#*#197328640#*#* or *#*#8255#*#*;
• Sony smartphones - *#*#3646633#*#*, *#*#7378423#*#* or *#*#3649547#*#*;
• Huawei phones - *#*#2846579#*#* or *#*#14789632#*#*;
• Mobile from ZTE - *#*#4636#*#*.

There is also a universal code that is suitable for most smartphones and tablets running on an MTK processor. You can look in the specifications of your device to see what processor you have installed. If this is a MediaTek (MTK) product, then try using the combination *#*#54298#*#* or *#*#3646633#*#*.

If it works, you will see the developer menu in front of you. Some engineering codes on Android do not work in operating version 4.2.1 and 4.2.2.

What third-party applications can be used to enter the engineering menu

How to enter the engineering menu on Android if Android codes does not work? There is a way. To enter the engineering menu, you will need one of the applications that will allow you to enter developer mode without entering a combination. IN official store Google Play There are several similar programs. One of them is “Launch the MTK engineering menu”.

To use it, you need:

1. Go to the Play Market and enter the name of the program in the search bar.
2. Download and install it.
3. Launch on your phone.

After that, you will see a couple of tabs with different settings.

The application allows you to perform various tests (for example, a processor stress test), obtain information about the modem or memory, and much more. You can also make changes to the hardware. To do this, you just need to open the appropriate sections and configure the settings. In this case, the phone will be on all the time.

An alternative option is the Mobileuncle tools program. You can download it on the Internet. Install the application, and then go to the “Engineer Mode” submenu. Almost all developer menu items will be available in it.

The engineering menu provides access to manual setting the “hardware” part of the smartphone. To enter you need to enter a special code or install an application, but there are a number of features that are worth paying close attention to. If you were unable to enter the engineering menu the first time, then you did not take into account the features of the device. It is worth immediately clarifying that any interference with the operation of the device may lead to its inoperability and loss of warranty.

Hidden capabilities of the system

At the last stages of setting up a smartphone, developers test the system for errors and check the operation of all sensors on the device. Especially for this, Android has a special subroutine built into it - the engineering menu, which provides access to hidden settings of the Android OS and allows you to reconfigure them yourself. In addition, the menu contains detailed information about the device. The full list of menu options is known only to the platform developers, so you should make your changes with caution.

Secret paths of developers

To enter the engineering menu, dial the code *#*#3646633#*#*. On some models, you additionally need to press the call key. It is worth considering the features of phones: for different brands there are different combinations of numbers. Android version does not affect the functionality of the engineering menu.

Enter a special code to enter the engineering menu

If no problems arise, you will be taken to an additional menu for fine-tuning your smartphone.

Enter the menu subsection

Depending on the system version and processor model, the engineering menu may be incomplete or missing. In the photo above there is a subsection of the menu with elements for testing smartphone sensors, setting up a USB connection, and performing internal and external memory tests.

If it doesn't work out the first time

Not all devices can access the engineering menu. Let's look at a number of common problems and ways to fix them.

Android is difficult operating system Unix based. If you can’t do something, you haven’t taken into account all the nuances of the functioning of a particular subroutine.

List of special codes

One of the common reasons for blocking entry to the engineering menu is an incorrect special code. The combination of numbers depends not only on the device model, but also on the type of processor. For example, most devices based on the MTK chip are equipped with an engineering menu. If we talk about Qualcomm, not all smartphones based on this platform have an engineering menu built into them. The list of combinations is given in the table. If you don't find the one you need, try entering a different combination.

Table: code options for different Android models

DIY engineering menu

If none of the special codes work, don’t worry. There are many applications on the network with engineering menu functionality. It is worth noting that the MTK prefix in the names eloquently indicates compatibility only with MediaTek processors.

The first option is Mobileuncle MTK Tools. In this program, in addition to required set There are several settings additional functions: firmware update, recovery update, GPS receiver enhancement mode and much more.

Mobileuncle MTK Tools provides a set of settings

Another program is MTK Engineering Mode. The program completely replicates the standard engineering menu.

MTK Engineering Mode repeats the standard engineering menu

For those whose device is not equipped with an engineering menu, there is another option: installing third-party firmware. Assemblies from third-party developers often contain a wide range of customization settings.

Where to begin

When you first enter the menu, you can get lost in the jungle of parameters.

Engineering menu settings

Settings open up enormous possibilities for users.

Depending on the hardware platform, some items may not be available or may be missing.

In this section you can configure settings mobile communications.

1. Auto Answer. You can enable or disable automatic answering of an incoming call.
2. Band Mode. Allows for manual mode choose frequency range for GSM module operation. You will see all technologies and frequencies for them supported by your smartphone model. If you wish, you can uncheck bands that are not used by your carrier. This will significantly save battery power. To save the settings, press the set button.
3. CFU Setting (Call forwarding Settings). The option enables or disables conditional forwarding. It must be supported by the operator.
4. AT Command Tool. A utility for developers that supports AT commands. This menu item will be of interest to programmers and developers. Using this menu, you can perform various queries directly to the system without visual add-ons.
5. Modem Test. Configuring compatibility of the “access point” option with various types connected devices.
6. Network Selecting. Here you can select mobile communication standards (GSM, WCDMA, LTE). For additional energy saving, turn off unused ones.
7. NetworkInfo. Select one or more options to display information about the status of parameters cellular communications. Once selected, open the additional menu (three dots in the upper right corner) and click Check Information. This option is convenient for checking the quality of cellular operator services.
8. GPRS. Setting up a connection to the mobile Internet, selecting an active SIM card (if there are several of them).
9. HSPA Info. Information about the 3G network if supported by your mobile operator.
10. Mobile data service preferred. The Internet will be given priority over voice traffic to increase data transfer speeds. Incoming calls may not go through.
11. Fast Dormancy. Allows you to save battery energy in third generation networks. The option must be supported by your telecom operator.
12. RAT Mode (Phone Info). Allows you to select the priority communication standard. You should change the parameter carefully, it blocks the settings of the Network Selecting item.
13. RF De-sense Test. You can select a frequency range and a specific channel to check the communication quality.
14. SIM ME Lock. This subsection allows you to configure the regional parameters of the GSM module (MNC, NCC) manually.

Photo gallery: mobile communication parameters

We get to the main window of the subsection Enable or disable auto answer Enable or disable conditional forwarding Configure the “Modem” mode Display information from the GSM module Configure Mobile Internet Select the priority of the connection type Configure the operation of the 3G mode Select the type of mobile connection Check the network power Configure regional communication parameters

Wireless interfaces

This section is intended for testing wireless data transmission modules (Wi-Fi, Bluetooth, FM).

1. Bluetooth. A wide range of settings and tests for the module of the same name in order to check the reception and transmission of data, and start the debugging mode.
2. CDS Information. Information about the parameters of wireless interfaces.
3. FM Receiver. Checking the FM module of the device.
4. Wi-Fi. Testing the module for transmitting and receiving information on the specified frequency channel.
5. Wi-Fi CTIA. Recording logs of wireless technology tests.

Photo gallery: wireless data transmission

Select the section for checking the device’s wireless modules Check the bluetooth operating mode Find information about the wireless interfaces Configure the FM module Check the operation of the WiFi module Write data about checking the WiFi module to a log file

1. Audio- fine tuning sound playback settings.
2. Camera - a set of parameters for taking photos and videos that are not included in the Camera application.
3. Driving Current Camera - takes current readings from the sensor in the camera circuit.
4. CPU Stress Test - performing tests of all subsystems central processor.
5. Deep Idle Setting - disable sleep mode in standby mode.
6. Sleep Mode Setting - sleep mode settings.
7. ChargeBattery - View battery information.
8. Sensor - sensor calibration.
9. Multi-Touch - checks the number of available points for simultaneously pressing the screen.
10. Location Engineer Mode - checking the parameters of the GPS module.

Photo gallery: equipment testing

Go to the section for checking electronic components Adjust the volume of the conversation speakers Adjust the camera's power supply Adjust the standby mode Adjust the frequency of the central processor Adjust the sleep mode View information about the battery Configure touch screen Checking the capabilities of the multi-touch function Setting up the GPS module

Adjusting the speaker volume

In the subsection you can adjust the overall volume level, headphone and speakerphone volume.

You should be careful when changing volume settings. All parameters are individual for specific model devices. Incorrect configuration may result in poor hearing performance.

There are a number of general parameters:

1. MaxVol - general volume level. The range of values ​​is from 0 to 160. The higher the number, the higher the volume.
2. Sph - volume during a telephone conversation.
3. Mic - microphone sensitivity.
4. Ring - speaker volume for incoming calls.
5. Media - volume level when watching movies, listening to music and playing games.

Very often, users are unhappy with the speaker volume during a conversation. To improve audibility, go to the Normal Mode menu and change the Sph parameter to 150. If the phone rings quietly when there is an incoming call, then you need to increase the value of the Ring parameter. We advise you not to set the value above 200, as this may damage the speaker. To make you better heard, change the Mic parameter from 100 to 172. This will increase the sensitivity of the speaker.

ROOT is a panacea for a smartphone

On a smartphone without root rights functionality The engineering menu is limited: some items are not displayed, changes made are not saved. Any interference with the operation of a smartphone requires open access to the system. Don't forget that gaining root access can damage your gadget and will void the device's warranty. We strongly recommend doing backup important information to a memory card and synchronize with your Google account and remove it to avoid data loss. To unlock full access to the system, you can use one of the existing methods.

Installing the application directly on the device (KingRoot)

Superuser access can be opened from a smartphone using special programs. Let's look at the sequence of operations using the KingRoot program as an example:

After this, you can safely change the parameters in the engineering menu, all changes will be saved. If the result is negative, we move on to the next method.

Obtaining superuser rights via PC (Kingo Root)

This method is slightly different big amount preparatory activities:

The engineering menu is used to configure the device and test the operation of the hardware. This is a built-in subroutine of the system, which is an indispensable tool for both experienced users and newcomers to the world mobile devices. However, it should be noted that manipulations with the engineering menu can render the gadget inoperative.

Not many people know about the existence of an engineering settings menu in devices based on Android OS. They can significantly expand the functionality and change many parameters, such as sound volume, camera settings, etc. To enter the Android engineering menu, you need to enter a special combination of characters in the dialing line telephone number. Moreover, each manufacturer has its own service code, consisting of numbers and symbols “*” and “#”. Let's consider the main issues related to the hidden engineering menu of the phone settings: how to enter, how control is carried out and capabilities.

The developers carefully check and calibrate each of their devices, so in most cases the user does not have to change any settings himself. But in some situations, you may need to make slight adjustments to certain parameters, such as the sensitivity of the built-in microphone or increasing the volume of the polyphonic speaker. Engineering is designed specifically for such cases. Android menu, which can only be accessed by entering a specific combination of characters. Please note that changing these settings is recommended only in special cases, as this may be dangerous for your phone. Therefore, only experienced users are recommended to enter the engineering menu on Android.

How to enter the menu?

In most cases, a special combination of numbers and symbols is used to enter the engineering menu. They must be entered in the line to dial the phone number. If your phone's processor is not MTK, then depending on the manufacturer's brand, the following engineering menu codes in Android are possible:

• Samsung. For phones of this brand, there are two options: *#*#8255#*#* or *#*#4636#*#*.
• NTS. Depending on the OS version and model, the following combinations can be used: *#*#3424#*#*, *#*#4636#*#* and *#*#8255#*#*.
• Sony. Dial: *#*#7378423#*#*.
• Huawei. Depending on the model, the following combinations are used: *#*#2846579#*#* or *#*#2846579159#*#*.
• Lg. By typing the combination 2945#*# on most smartphones of this brand, you will be taken to the 1st engineering menu and can read the instructions for use.

For most Chinese smartphones such as Lenovo, Acer, Prestigio, etc. You can open the engineering menu using the code *#*#3646633#*#*. Immediately after entering the desired combination in the line for the phone number, it will disappear and open service mode settings. If this does not happen, then you need to start it by pressing the call button. It is recommended to remember or write down the value of the initial parameters that will be configured. Also, before getting into the engineering menu, remove all running applications and active processes.

An alternative way to enter the engineering menu

Some phones and tablets have a separate program for this, which you need to download from the Google branded store - the playmarket. Having launched it, the user finds himself in the service settings section of his device, just as when typing the code. For example, you can download the launch of the mtk engineering menu, the Mobileuncle MTK Tools application, which is designed specifically for devices with the appropriate processors. Another way to enter the developer menu for owners of such smartphones is to enter the code *#*#3646633#*#*. We recommend watching a training video that shows how to open the service settings mode on various brands Android smartphones 5 and below.

Engineering menu options

A user who has access to the service settings mode in Android has extensive opportunities to expand the functionality of their device. Through the engineering menu the following become available:

1. Determination of the level of harmful radiation.
2. Testing available types wireless connection, such as Bluetooth, Wi-Fi, etc.
3. Checking the GPS signal strength on Android and determining the exact location.
4. Audio setup. Set the sound level for speakers, headphones and microphones.
5. Camera settings.
6. Testing the central processor, video accelerator, flash and RAM.
7. Detailed description of the battery.
8. Testing mirco SD card.
9. Examination micro USB port.
10. Temperature sensor. Shows battery and CPU heating.

Depending on the device used, the list of options presented above when entering the engineering menu may vary. Accordingly, the more sensors and modules a smartphone has, the more settings it has.

Let's look at how to change the volume settings using the example of a smartphone with an MTK processor. Before you open the required service you must enter a combination of characters to enter engineering mode. A long list of settings will open, among which you need to find the “Audio” item and click on it. After this, a menu will appear with several modes: when nothing is connected to the phone, a headset is connected, the speaker is on, etc. For each of these modes, more than 5 points are available for adjustment.

To change parameters, you need to erase the old value in the desired cell and write a new one, and then click on the “set” button. The assigned value must not fall outside the range specified in parentheses. It is also not recommended to use the maximum available value, as this will distort the sound.

Android service codes

In order to quickly test your device for the functionality of basic functions and sensors, there are special codes Android. You need to enter them, as to enter engineering mode, in the line for dialing a telephone number. Since most of the combinations are the same for all models and brands of smartphones, we present the general and most important ones in the following list:

• *#*#4636#*#* - general information about the phone, battery status and usage statistics.
• *2767*3855# — full reset settings, hard reset.
• *#*#34971539#*#* - detailed camera specifications.
• *#*#2664#*#* — Android touchscreen calibration.
• *#*#232331#*#* — bluetooth test.
• *#*#8351#*#* — enable voice dialing registration mode.
• *#*#1111#*#*, *#*#2222#*#* — viewing FTA software and hardware versions.
• *#*#0*#*#* — display test.
• *#*#0673#*#* - audio test.

It is also worth noting that for some brands there are additional combinations, for example for displaying the EPST menu and testing functionality. IN modern models Samsung phones, such as Galaxy s6, the diagnostic menu can be opened by dialing *#0*#. And Motorola devices have built-in secret menu. Before turning it on, you need to enter the combination *#*#4636#*#*.

Majority Android devices have hidden functions, which include engineering Xiaomi menu, and any other phone. It is hidden primarily from inexperienced users so that they do not mess things up.

Why do you need an engineering menu?

The engineering menu is used by developers to final configure the device. Here you can check the operation of all sensors and test the main components. There are about 25 different types of tests in total.

How to open the engineering menu on Xiaomi smartphones?

There are 2 ways to enter the Xiaomi engineering menu:

Method number 1 - through dialing

This method works for everyone Xiaomi smartphones Mi and Redmi lines - you need to enter in dialing mode: *#*#6484#*#*. If this code doesn't work, try it *#*#4636#*#* .

Method number 2 - through settings

The algorithm of actions is simple:

1. Open " Settings» smartphone
2. Go to the menu " About the phone«
3. We find the item “ Kernel version" and quickly click on it 5 times

It is worth noting that depending on the model of your smartphone, the engineering menu may differ.

This is what the engineering menu looks like on Xiaomi Mi 8 Lite:

In this case, the menu has 32 items (their number may also differ depending on the smartphone model):

1. Check version info— information about the version. Here you can see the IMEI and serial number;
2. SIM card- shows SIM cards installed on a smartphone;
3. Support TFCard— information about a third-party SD drive;
4. touch sensor— touchscreen test;
5. Display— display test;
6. Receiver— standard speaker test;
7. speaker— conversational speaker test;
8. Light sensor— light sensor test;
9. Proximity sensor— proximity sensor test;
10. OTG— testing external USB;
11. Charger test— charging check (you need to connect the charger);
12. Battery indicator— displays the charge level and temperature of the battery;
13. Read camera— rear camera;
14. Rear sub camera— rear auxiliary camera;
15. Rear dual camera— rear dual camera;
16. Front camera- front-camera;
17. FPC fingerprint sensor— checking the fingerprint sensor;
18. Keyboard test— checking the “volume up”, “volume down” and “lock” keys;
19. Vibrator test— vibration test;
20. Notification light (LED)— flashlight and display brightness test;
21. Main MIC— test of the main microphone;
22. Top MIC— test test of the top microphone;
23. Headset test- headphone test;
24. Wi-Fi AP Scan— scanning Wi-Fi networks;
25. Wi-Fi Address- address Wi-Fi networks, to which the smartphone is connected;
26. Bluetooth scan— search for bluetooth devices;
27. Get Bluetooth address— bluetooth address of your device;
28. Accelerometer— checking the acceleration sensor;
29. Gyroscope— checking the gyroscope;
30. Magnetic sensor— magnetic sensor test;
31. GPS— checking the GPS sensor;
32. SAR Sensor— level of electromagnetic radiation.

And here's what it looked like on the old one Xiaomi Redmi 3s:

The menu consists of five items:

1. Automatic Test. All parameters will be tested automatically.
2. Single Item Test. Here you can run any of the tests separately.
3. Test Report. Here you can view the test results.
4. SW add HW version. Find out the version of your smartphone.
5. Device View. All information about the device's hardware.

If everything is clear with points 1,3,4,5, then the second one needs to be discussed separately, since it includes a bunch of tests.

• Key– checking the functionality of physical buttons
• Blacklight– testing the display for brightness
• TouchPanel– sensor testing
• TFlash– checking the memory card
• Bluetooth– searches for all available devices
• SIM Card– checking the availability of SIM cards
• Vibration– vibration test
• Loopback– tests the conversational microphone for recording and playback
• LCD– display colors
• GPS– search for satellites
• Gyro– gyroscope operation
• G-sensor- speed sensor
• Proximity Sensor– responsible for fading the screen during a conversation
• Optical Sensor– optical sensor
• Magnetic Sensor– magnetic sensor
• RTC– built-in clock
• Speaker– checking the speaker
• Receiver– checking the standard speaker
• Headset– test the headphone jack, headsets and sound playback
• LED– notification indicator
• FM– checking the radio operation
• Camera– testing the camera and flash
• Battery– battery and charging operation
• WiFi– looking for access points
• Torch– checking the flashlight

As you can see, using the engineering menu on Xiaomi you can get a lot of information. An experienced user will be able to use it to roll back the smartphone to standard (factory) settings, test the operation of all sensors, find out more detailed information about the device, optimize battery consumption and much more.