When the screen of a Xiaomi or Redmi smartphone starts flashing, pulsating or lighting up in black during an incoming call, it can cause panic in any user. This phenomenon is often confused with a serious hardware failure of the matrix, but in the vast majority of cases the problem lies in the software settings of the MIUI or HyperOS system. Various functions designed to improve the user experience, such as “pocket mode” or “call indicators”, can conflict with each other, creating visual noise.
The main reason for this behavior is the proximity sensor, which is activated when the phone is held to the ear, blocking the screen to avoid accidental cheekstrokes. If this sensor is not working correctly or its sensitivity is set too aggressively, the screen will constantly turn on and off, creating a blinking effect. In addition, there are specific themes for design and setting the notification flash, which can also provoke similar visual effects during the incoming connection.
In this article, we will take a closer look at all the possible causes of flashing screens when calling on Xiaomi devices, learn how to properly configure the proximity sensor, where to turn off intrusive visuals, and what to do if the problem is caused by physical contamination or protective film. We will look at solutions for both standard settings and hidden engineering menus.
Causes of screen blinking and call indicators
Before we start radical methods of solving a problem, we need to understand the nature of the failures. Most often, the flashing of the screen is caused by the system's attempt to lock the display in response to the action of the proximity sensor. The smartphone "thinks" that it is in the pocket or ear, and extinguishes the backlight, but due to false alarms of the sensor, the screen immediately lights up again. This cycle can be repeated indefinitely until the call is received or reset.
Another common reason is to activate the Light Effects or Notification Flash feature. On many Redmi and POCO models, this option causes the LED flash or even the screen itself to pulse in a certain color. If a third-party launcher or a theme with low code quality is installed on the system, these effects may not display correctly, causing the entire caller interface to flicker.
It's also worth considering the effects of protective glass and film. If the accessory closes the area of the upper speaker where the sensor is located, or has a too thick edge, it creates optical interference. Infrared radiation of the sensor is reflected from the film and returned back, causing the system to think that the object is close to the screen, as a result, the lock mode is activated, and the screen goes out, and then lights up again when the system tries to check the status of the sensor.
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Check if the protective glass or thick case covers the area above the top speaker, and often this is what causes the proximity sensor to falsely fire.
Setting up the proximity sensor through the engineering menu
The most effective way to eliminate false positives is to calibrate the proximity sensor, and there's a special engineering menu in the MIUI shell that allows you to test and adjust the sensors, and you don't need root rights to access it, you just need to enter a special code in the Phone app, which allows you to see the current readings of the sensor and reset them to factory values.
To get into the testing menu, open the call app and dial the combination ##6484##. If the code doesn't work, try ##4636## or go to the Service and Feedback (or Feedback) menu in the settings, where the top right corner often hides the "Testing" item. Find the "Proximity Sensor" or "Approximation Sensor" test in the list. When you click on it, you will see the current value that should change when you close the top of the screen with your hand.
If the values jump randomly or do not change at all, press the button "Calibrate" or "Get Data." During the calibration process, remove your hand from the screen and follow the instructions on the display. Usually you need to remove and close the sensor several times. After successful calibration, the system will retain the new reference values, which should eliminate the problem with the constant flashing of the screen during a conversation.
☑️ Calibration of the proximity sensor
Disabling pocket mode and locking in the pocket
Pocket Mode is designed to prevent accidental taps when the smartphone is in your bag or pocket. It uses a proximity sensor to detect where the phone is in a confined space. However, the algorithms for this feature on Xiaomi are sometimes overly sensitive, leading to the screen being turned on and off constantly even outside your pocket, especially if the phone is lying on the surface of the screen down or covered with fabric.
To disable this feature, go to the standard Phone app you use to dial a number. Click on the menu icon (three dots or gear) and select Settings. In the list that opens, find the Incoming Calls or Pocket Mode section, where you need to move the switch to an inactive position, which will prevent the system from locking the screen based on the sensor readings during the call.
If standard means fail to disable the feature, you can use the advanced settings through the Security app. Open it, go to the Antispam or Lock section, which can also duplicate the call filtering and incoming behavior settings. Disabling pocket mode often solves the problem when the screen goes out and lights up when the phone moves near the body.
⚠️ Warning: After you turn off the mode in your pocket, be careful when putting your phone in your bag.The screen may not lock, which will lead to accidental calls to contacts from the list of the latter or unlocking the device by unauthorized people.
Flash and light indicators control
Many users want their smartphone to flash when they call, but sometimes it doesn't work properly, causing a strobe effect or not turning off after they respond. The settings for this feature are in the special features section. The path to it may vary slightly depending on the Android version, but it usually looks like this: Settings → Advanced Settings → Special features. Here you need to find the "Flash for notifications".
In some versions of MIUI, flash control is set to the phone app itself. Go to the call profile, select Settings → Incoming Calls, and look for Flash or Call Indicator. If there's a tick, try to uncheck it and check the result. It's also worth checking the design settings, as some visual styles replace the standard call interface with your own, with built-in but poorly optimized blinking effects.
One of the things that deserves a special attention is Screen Flash, which can be built into some themes or third-party calling apps. It makes the whole screen pulse in bright color. To turn that off, make sure you use a standard Classic or Default theme. If you use a third-party theme from Themes, try switching to a standard one and check if the blinking disappears.
Comparison of methods of solving the problem
The right method of decision depends on the specific model of your device and the version of the operating system. Below is a table that will help you to orient what action will be most effective in your case. Not all methods are universal, and sometimes a combination of several steps is required to completely eliminate the defect.
| Method of decision | Efficiency | Difficulty | Risks. |
|---|---|---|---|
| Resetting sensor calibration | Tall. | Medium | Minimum |
| Disabling pocket mode | Medium | Low. | Random taps |
| Replacement of the topic with standard | Medium | Low. | Loss of visuals |
| Resetting phone settings | Maximum | Tall. | Loss of data |
As you can see from the table, the safest and often most effective method is to calibrate the sensor. However, if the software failure is deeper, deeper intervention may be required. It is important to understand that resetting is a last resort, which should be resorted to only if other methods have not worked.
If none of the software methods worked, and the screen continues to blink even after a complete reset, there is a high probability of a physical malfunction, this may be a departing display plume, a malfunction of the proximity sensor itself, or problems with the power controller, in which case the software settings will not help, and you will need a diagnosis in the service center.
Impact of Design Themes and Third-Party Applications
MIUI is famous for its flexibility in terms of personalization, but it is the themes that often become the source of bugs. Third-party themes downloaded from the Themes store can contain errors in the code of the call interface. For example, the theme can force the effect of "breathing" the screen or improper operation of the light sensor. If the problem appeared immediately after installing a new theme, go back to standard design.
And third-party dialing apps, like Truecaller, Google Phone, or various number detectors, can also have an impact, and they have their own interface and sensor settings, and go to the settings of that app and find the "Call Screen" or "Actions" section, and try to turn off all visuals, animations, and smart lock features.
Hidden settings in ADB
Also worth checking is the Security app, which is system-based on Xiaomi. Its settings sometimes hide items regulating screen behavior and memory cleaning, which can indirectly affect the stability of the call interface. Clearing the cache of this application through the Apps menu → All Apps → Security → Clear can eliminate temporary errors.
Hardware problems and physical factors
You can't rule out the physical nature of the problem. If the screen is flashing, but the sensor settings are normal, look at the top of the display when the light is off. Turn on the flashlight and illuminate the speaker area. If you see cracks, chips or traces of moisture, this can be the reason for short circuits in the sensor circuit. Moisture is especially dangerous, because it changes the refractive index of light, causing the sensor to "see" obstacles where there are none.
Another important point is the quality of the protective glass. Cheap glass often has opaque edges or insufficiently accurate cutouts. If the black glass frame comes to the sensor, flashing is inevitable. Try to carefully remove the glass (if possible without damage) and check the phone without it. Also make sure that the screen is free of severe dirt, grease or stickers at the top.
⚠️ Warning: If the phone fell or was hit, the plume connecting the proximity sensor to the motherboard might have left, in which case a simple reboot will not help, you will need to disassemble the device.
In rare cases, the problem lies in the display module itself. If the blinking is accompanied by a change in color reproduction, the appearance of stripes or image artifacts in other applications, this is a clear sign of degradation of the matrix or screen controller, in which case the only solution is to replace the display module in the authorized service center.