Xiaomi’s smartphones, and the popular Redmi Note 7, are powerful, accessible not only to users but also to service center engineers. This hidden section of the MIUI operating system allows for deep diagnostics of hardware components, calibration of the display and testing of sensors without having to connect to a computer. For owners who want to check the device before buying from hand or identify the cause of unstable work, access to this data becomes a critical tool.
However, getting into this section requires caution. The engineering menu is not just a set of settings, but a direct hardware management interface, where careless action can knock factory calibrations. Unlike standard settings, changes are applied instantly and often without the possibility of rolling back through the back button. So, before any manipulations begin, you need to clearly understand what each item is responsible for and avoid chaotic button pressing.
In this article, we will take a look at all the legal ways to access the diagnostic interface on the Redmi Note 7, consider the most useful features for checking the condition of the device and explain how to interpret the data obtained. You will learn how to check the “broken” pixels, assess the sensitivity of the touch screen and even find out the real battery mileage, which is often hidden by unscrupulous sellers in the secondary market.
The main ways of entering through USSD-code
The fastest and most proven method of activating hidden menus on Xiaomi smartphones is the use of special command lines, known as “Stealthy Menus” (Source: “Stealthy Menus”). USSD-These commands are entered in the same way as the phone number to call a subscriber, but instead of connecting to the operator, they run system applications. For Redmi Note 7, the most universal code is ##64663##, which immediately opens the interface. CIT (Customer Interface Test: Enter the characters carefully, as the menu can open immediately after entering the last digit, without the need to press the call button.
There is also an alternative code ##4636## that opens the phone test menu, which is more about software and network settings, but also contains valuable information about battery status and usage statistics. If standard codes fail, which sometimes happens on certain versions of MIUI firmware, you can try entering the code ##6484##. In some cases, the system may require confirmation of rights or simply do not respond if the relevant system component has been removed or changed by the manufacturer.
It is important to note that these codes do not require the presence of SIM-card or active Internet connection, because the request is processed locally on the device, however, if you have custom firmware installed or have made deep changes to the system file build.prop, some commands may be blocked. In such situations, it is worth trying to restore the stock version of the shell or use alternative methods of access through the developer menu.
Enter through the developer’s settings and menu
If you can't enter digital combinations for some reason, there's a graphical way to activate the test mode. You'll need to go to the standard device settings menu. Find the About section and click 7-10 times in a row on the MIUI version. This action activates the hidden developer mode, which will be notified by a pop-up message at the bottom of the screen.
Inside the developer menu, you need to scroll down to the Debugging section, and you can have "Enable Factory Tests" or a similar wording that depends on the Android version and shell, and activating this switch makes the test shortcut available in the general app menu. This label is often called “testing” or "CIT", And it's like starting it. USSD-The same diagnostic interface is opened.
☑️ Check before entering the menu
Be prepared that some global versions of Xiaomi firmware may have different depths than the Chinese versions, and in global builds, some engineering features may be hidden or removed for security and regional standards. If you do not find the right switch, return to the method of USSD-The most reliable option for the Redmi Note 7.
Diagnostics of the display and touch screen
One of the most sought-after features of the engineering menu on the Redmi Note 7 is to check the quality of the matrix and the responsiveness of the sensor. IPS-In a high-resolution screen, the presence of broken pixels or "dead zones" of the touchscreen can significantly reduce the comfort of use. CIT Select the item associated with the display (usually marked as Display or Touchpanel) to run the automatic or manual test.
When you check the touchscreen, the screen is painted in a certain color, and you're asked to swipe your finger over the entire surface. The system records every touch, and if you draw the line, it should be continuous. Line breaks indicate problems with the digitizer. This is especially true for used devices where substandard parts may have been replaced or where the glass has microcracks that are invisible to the eye.
⚠️ Note: Do not use sharp objects or metal-tipped stylus during the touchscreen test, as this may damage the oleophobic coating or the touch layer itself.
To test the display for broken pixels, a mode is used that consistently floods the screen with red, green, blue and white. Carefully examine the image at maximum brightness. If you see points that do not change color or glow differently than the rest of the matrix, this indicates a defect. It also allows you to evaluate the uniformity of the backlight and the presence of illumination at the edges, which is often found in budget models.
Checking the proximity sensor
The proximity sensor is a component that turns off the screen when you hold your phone to your ear. On the Redmi Note 7, the sensor often causes complaints that the screen may not go out or turn on after a conversation is over. The engineering menu has a separate Proximity sensor test that allows you to calibrate it or check current readings.
In the test mode, you'll see two values: distance in centimeters and logical state (0 or 1). Close the top of your smartphone with your palm, the value should change, and the logical status switch. If there's no reaction, maybe the sensor is contaminated, covered with a protective film or has a software failure. In some cases, there's a calibration function available here that resets the reference distance values.
Why can the sensor lie?
A common problem is software failure when the sensor sticks in proximity, in which case a simple calibration through an engineering menu often solves the problem without the need for flashing, but if the physical values of the distance do not change even when closed with the hand, it can be a hardware malfunction that requires the replacement of the plume or module.
Testing vibration, sound and microphone
The audio tract and the vibration module are other important components that can be easily checked in a hidden menu, and the Vibrator section allows you to start the vibrator motor for a few seconds, which helps you determine whether it has become quieter over time and whether there are any extraneous rattling sounds that may indicate a mechanism is unstick or dust is hitting.
To test the sound, you use a complex test that involves playing the melody through the main speaker and through the conversational speaker, and you're asked to hear the sound and confirm it with buttons on the screen, and you're testing the microphone separately, and you're going to press the record button and you're going to say the phrase and then listen to it, and the recording quality is going to be clean, without much noise or distortion.
| Component | Type of test | Normal result | Possible problem |
|---|---|---|---|
| Vibromotor | Mechanical vibration | Smooth, palpable vibration | Freaking, low-impact |
| Main dynamics | Reproducing the melody | Pure sound without wheezing | Wheezing, lack of sound |
| Microphone | Recording and reproduction | Leading speech | Noise, silence, echo |
| Speaking speaker | Test horn | The sound in the ear | Silent sound, distortions. |
If you find that only one earphone has sound (connected through a 3.5 mm connector) or the microphone doesn’t work in certain applications, this may indicate a conflict of software settings. However, if the problem is reproduced in the engineering menu, the probability of hardware failure is high.
Information about the battery and software version
The battery section is often the subject of scrutiny when buying a used Redmi Note 7. The test menu not only shows the current percentage of charge, but also more technical data such as voltage, temperature and, most importantly, status (Good, Bad or Overheat).
This box also shows detailed software information, which you can see the exact version of Android, the MIUI build number, the firmware compilation date, and the region, which is critical to determining whether a device is up to date and whether you can get security updates, and if you have a non-standard version of the software, you can see that you're trying to stream the Chinese version to a global version.
💡
Pay attention to the temperature of the battery at rest. If the engineering menu with the screen off and no running processes temperature is above 30-32 degrees, this may indicate battery wear or background processes that cause overheating.
For lithium polymer batteries installed in the Redmi Note 7, the normal operating voltage is the range from 3.7V to 4.2V. Significant deviations in the lower direction at a high percentage of charge can indicate a "memory effect" or degradation of the battery's chemical elements.
Frequent mistakes and ways to solve them
When working with the engineering menu, Xiaomi users often face a number of typical problems, one of the most common is the inability to exit the test. In some versions of the MIUI, the Exit or Back button may not respond, especially if the test is frozen, in which case it helps to hold the power button for a long time (about 10-15 seconds) to force the device to restart.
Another problem is the lack of response to code entry. If your smartphone doesn't open the menu after entering ##64663##, check if the input service is disabled in the keyboard settings or if it's worth banning calls for unknown numbers (although USSDs are not calls, some filters can block entry of asterisks), and also make sure you're in the main dial menu, not in the contact search.
⚠️ Warning: Do not try to change the values in the sections marked as "Factory" or "Calibration" if you are not sure about your actions. resetting the factory calibration of the camera or modem can lead to malfunctioning of the device, which is difficult to fix without service equipment.
If the menu opens but all tests show an error immediately, it can be a sign of a major controller malfunction or damage to the plumes. In such cases, software methods, including factory resets, may not help, and a diagnosis at an authorized service center may be required.
💡
The engineering menu is a powerful diagnostic tool, but not a panacea; it helps to detect a malfunction, but it can not always fix a software failure that requires flashing or replacing components.
Security and Return to Original Settings
While the engineering menu itself does not erase user files, accidentally activating Factory Reset within this menu will result in a complete loss of photos, contacts and applications. Therefore, it is highly recommended to back up important data to the Mi Cloud or computer before logging into any partitions related to memory or system.
After all the necessary tests and checks, you don't need to do any special actions to "get out" of the engineering mode globally. Just close the testing application or restart the smartphone. All changes that you haven't explicitly confirmed (for example, calibration), but which the system has deemed temporary, will be reset. Permanent changes (as in the case of sensor calibration) are stored in the device's memory.
Using this knowledge allows the owner of the Redmi Note 7 to feel more confident when using the gadget. Regular check of the main systems can help to notice the degradation of components in time and prolong the life of the smartphone. Remember that competent diagnosis is the first step to high-quality repairs or profitable sale of the device.