Owners of Xiaomi, Redmi and Poco smartphones often face the need for deep diagnostics of the device, which goes beyond standard settings. The engineering menu, also known as CIT (Component Integration Test), is a hidden part of the operating system, designed to test hardware components in the factory. This is where you can check the operation of each sensor, screen, vibrator and communication module without installing third-party applications.
This section is usually closed to the average user to prevent accidental changes in critical parameters that can lead to unstable operation of the gadget. However, knowing the right login methods, you get a powerful tool for self-identification of faults. In this article, we will look at all the current login methods, including universal codes and methods for devices with unlocked bootloader.
It should be noted immediately that the interface of the engineering menu may differ depending on the version of the MIUI shell or HyperOS. Some items may be called differently, but their functionality remains unchanged across different models.
What is it? CIT-The regime and why is it needed
The engineering menu in Xiaomi smartphones is not just a list of hidden settings, but a full-fledged diagnostic package. CIT stands for component integration testing, which was originally created by engineers on assembly lines to quickly check the quality of each assembled device before packaging, and users accessed it as a self-diagnostic tool to determine whether a particular hardware module is working correctly.
This is especially true when you buy a used device or when you drop a smartphone. Instead of wondering why the microphone is not working well or why the battery is going down quickly, you can run an automatic test. The system will check the response of the touchscreen, the presence of broken pixels, the accuracy of the accelerometer and the operation of all the buttons. This allows you to localize the problem before going to the service center.
This section also contains information about driver versions, IMEI-all-SIM card codes, MAC-This data is often needed to flash the device or recover from software failures. Knowing the exact model of the sensor or display helps find the right files to replace or calibrate.
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Before selling a smartphone, run a full test in CIT-mode - this will increase the buyer's confidence and prove the serviceability of all the functions of the device.
Universal method of entry through dialing
The easiest and safest way to get into a hidden menu is to use a special menu. USSD-This method works on the vast majority of Xiaomi smartphones with original firmware installed. You don't need root rights or a computer connection, just the Phone app».
To activate the mode, you need to dial the following character combination: ##64663##. Once you enter the last character (grating), you do not need to dial - the menu will open automatically. If the screen blinks and the list of tests with the MI or Android logo appears, then access is successful. On some models, especially with global firmware, the code can be changed to ##4636#, which opens the test menu.
It is important to understand that the code ##64663## is the main one for entering the full CIT. The command ##4636## is more often used to configure the preferred network type (LTE/3G/2G) and view usage statistics, but does not contain complete hardware tests. If the first code does not work, try the second one, but the first one is needed for a full hardware diagnosis.
⚠️ Note: In some regions or on certain versions MIUI Communications operators can block the entry USSD-If the set doesn't work, try typing the code in the Phone app through the set, not through the contacts.
Entering through the "About Phone" settings
If the code is not working for some reason, there is an alternative way through the GUI system, which often works even when the system is not working. USSD-commands are locked by the operator or software. It requires several sequential actions in the settings menu.
First, go to Settings → About Phone. Here you need to find MIUI Version or OS Version. You need to quickly click on this item 7-10 times in a row. Unlike activating developer mode, you may need to enter a special code here or just repeatedly clicking will lead to a new menu.
However, the more reliable way through the settings looks different. Go to Settings → About Phone → All settings. Find the Kernel version and click on it 5 times. Then, in the upper right corner of the screen, the gear icon or menu with the CIT logo may appear.
Why can’t the code work on the global firmware?
Using ADB for Advanced Users
For those who are not afraid of the command line and have access to a PC, there is a most reliable login method that ignores the locking of the interface. Using the Android Debug Bridge (ADB) debugging bridge allows you to run hidden system activities directly, this method requires pre-activation of the developer mode and enable debugging over USB.
First, connect your smartphone to your computer and make sure the device is identified in the system. Open the command line or terminal in the ADB folder and type a command to trigger CIT activity. This action will force the desired interface to open, even if the shortcut is hidden.
adb shell am start -n com.miui.cit/com.miui.cit.CITActivityIf no standard activity is found, run the common Android test interface, which is also available on Xiaomi devices:
adb shell am start -n com.android.settings/.TestingSettingsThis method guarantees entry 99% of the time, as it addresses system components directly, bypassing the launcher user interface, and is especially useful if the screen is partially down and you can’t get to the menu in the usual way using external control tools.
☑️ Preparation for work with ADB
Basic functions and tests in the engineering menu
Once you've successfully logged in, you'll see a list of tests, each one of which is responsible for checking a specific module. The interface is usually presented as a list with buttons. When you click on any item, you run an automatic or manual check, and let's look at the most important ones that will help with diagnosis.
Special attention should be paid to the Touchpanel (touchscreen) and Display (screen) tests. In screen screen screen screen mode, the device will consistently change colors (red, green, blue, white, black), which allows you to identify broken pixels or uneven backlight. Touchscreen is checked by drawing lines throughout the area — if the line is interrupted, then there is a problem in this area with feelings of “truth”.
Also critical are the soundtrack tests: Receiver (talk speaker), Speaker (loud speaker) and Microphone (microphone) -- in microphone recording mode, you can see the visualization of the sound wave, which helps you see if the device can hear you at all. The vibration test will check the mechanical response of the motor.
Below is a table of basic codes and features for quick navigation through the diagnostic menu:
| Name of the test | Function | What we check. |
|---|---|---|
| Version | Information | Software versions, drivers, IMEI |
| Touchpanel | Diagnostics | The sensor's performance by zone |
| RGB | Visual test | Broken pixels and color reproduction |
| Vibrator | Mechanics | The presence and strength of vibration |
| Wlan / BT | Connection | Search for networks and Mac addresses |
Frequent problems and ways to solve them
Users often experience a situation where nothing happens after entering the code, which may be due to the fact that your device has a modified firmware or a specific version installed. MIUI, where the input is closed, in such cases, it helps to clear the cache of the Phone application or use third-party caller applications that support sending USSD-team.
Another common problem is the test menu crashes immediately after opening, which often indicates damage to system files or conflicting access rights. If you previously received Root rights, it may be that the system files have been changed, in which case it is recommended to check the integrity of the system or perform a reset to factory settings.
Sometimes tests can show a Fail, even though the device is working normally. For example, an accelerometer test may fail if the phone is not on a perfectly flat surface. A GPS test requires an open sky and time to warm up the module. So a single test failure does not always mean a breakdown.
⚠️ Warning: Do not try to change the values in items labeled "Debug" or "Engineering" unless you know exactly what they are responsible for.Resetting the sensor calibration can lead to incorrect autobrightness or screen rotation.
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If the equipment test shows Fail more than twice in a row under different conditions, a physical malfunction of the module requiring replacement is likely.
Security and exit
It's important to understand the difference between a diagnostic menu and a recovery mode. While in CIT, you can't accidentally lock your phone or delete data if you're just running tests. However, leaving the menu can sometimes be difficult if the interface freezes.
For a normal exit, you usually just press the back button or the cross in the corner of the screen. If the system responds to presses, just leave the application. If you freeze completely after a failed test, a forced reboot will help. Press the power button for 10-15 seconds until the device vibrates and restarts.
Remember, these tests are not required to be used regularly, they are a tool for troubleshooting, not for daily use, and frequent full inspection of all modules can put unnecessary strain on the processor and battery with no apparent benefit.