Modern Xiaomi smartphones are equipped with advanced biometric protection technologies, among which the fingerprint scanner is a leader in speed and convenience. However, device owners often face a situation when the sensor stops reading the finger correctly the first time or completely ignores touch, this can be caused by banal surface contamination or software failure in the module.
In this article, we will discuss how to properly clean the fingerprint scanner on Xiaomi to restore its sensitivity. We will look not only at physical cleaning methods, but also at software settings that are often ignored by users, although they can cause unstable work.
Ignoring the problem can cause the unlock function to fail completely, which will cause you to enter a PIN or a pattern lock every time. Proper sensor care extends the life of the device and ensures reliable protection of personal data. Let's get started with troubleshooting.
Reasons for poor fingerprint scanner performance
Before you start to act, you need to understand the nature of the problem. Scanners built into the power button or located under the screen are extremely sensitive to external factors. The most common cause is the accumulation of fat, dust and sweat on the surface of the sensor. Even a microscopic film of fat can distort the pattern of papillary lines that the sensor reads.
If the skin is too dry, wet or contaminated, the phone will not be able to identify the owner. Security glass owners often forget that the thickness of the glass affects the operation of optical scanners under the screen. MIUI and HyperOS have compensation algorithms, but they are not all-powerful.
⚠️ Warning: Using aggressive cleaning chemicals can damage the oleophobic screen covering or damage the scanner module itself, leading to costly repairs.
Software failures also play a role: After upgrading the system or installing heavy applications, the cache of the security module can overflow or get damaged, in which case physical cleaning will not help, you will need to interfere with system settings or flash the biometric data.
Preparation of cleaning tools and materials
You don't need a sophisticated technical arsenal to clean the sensor safely, and the main rule is to avoid abrasives and excess moisture, the ideal solution is to use a special microfiber for optics or screens, and ordinary paper wipes can leave small villi or scratches on the surface.
If the contamination is severe, you can lightly moisten the fabric with distilled water or a special spray for screens. Never pour liquid directly onto the phone! Also have a can of compressed air on hand to remove dust from hard-to-reach places around the button.
- 🧹 Microfiber wipe – the main tool for polishing.
- 💧 Distilled water or isopropyl alcohol (minimum amount).
- 💨 A compressed air canister for blowing out dust.
- 🔦 Lantern - to inspect the surface at an angle.
Make sure your hands are clean and dry before starting the procedure, which will prevent re-contamination of the surface just cleaned. If you have a protective glass, make sure it does not crack in the area of the scanner, as moisture can penetrate through the crack.
Physical cleaning of the sensor: step-by-step instructions
The cleaning process depends on the type of scanner you have on your Xiaomi smartphone. In side scanner models (on the power button), the process is easier because the sensor has clear boundaries. In models with scanners under the screen (usually at the bottom of the display), special care is required.
Turn off the screen of the device first, so you can see the pollution when you light up with a flashlight. Rub the surface with a microfiber in a light circular motion. If the plaque is not removed, wet the cloth slightly. The movements should be smooth, without much pressure, so as not to damage the display matrix or the mechanical button.
☑️ Cleaning checklist
After cleaning, allow the surface to dry completely within 1-2 minutes. Do not try to unlock the phone with a wet finger. If the scanner is sideways, blow a gap around the button with air to remove fine dust that may have stuck in the gap between the button and the body.
⚠️ Note: Do not use toothpicks or needles to pick around the scanner button, as it may damage the mechanism of the button's motion or the tightness of the body.
Pay special attention to the edges of the scanning area, often there is dirt that prevents the correct positioning of the finger. After the procedure, wipe the screen again with the dry side of the tissue to remove possible stains.
Customization and calibration in Xiaomi system
If the physical cleaning didn't work, the problem could be software, and MIUI-based Android allows you to manage your fingerprints in a flexible way, and the first step is to remove old, possibly poorly preserved, fingerprints and re-introduce them.
Go to the Settings menu → Passwords and security → Unlock fingerprint. Here you'll see a list of saved fingers. Delete all existing records. This is to reset old data that might have "remembered" a dirty or wrong angle of touch.
When you add a fingerprint again, follow the on-screen guidelines, but with one caveat: Try to touch the sensor with different parts of your finger, including the edges and center, and the system will create a more complete digital cast, which will increase the likelihood of successful unlocking in the future.
| Action. | The way is on the menu | Purpose |
|---|---|---|
| Deletion of data | Settings → Passwords → Delete | Resetting old patterns |
| Addition of new | Settings → Passwords → Add | Creating a clean cast |
| Acceleration of unlocking | Settings → Additional → Acceleration | Reduced delay (if available) |
| Verification of updates | Settings → The phone. → Version. MIUI | Installation of bug fixes |
Some models have a feature called "Accelerate Unlock" or similar, which can improve sensor responsiveness, although it reduces security slightly, and for everyday use, this is often an acceptable trade-off.
Influence of protective glasses and covers
The protective film or glass is the main enemy of scanners embedded under the screen. Optical scanners read the reflection of light from a finger through the display. If the glass is too thick, matte or has defects in the scanning area, reading will be impossible.
Check if there are any air bubbles or cracks above the scanner, and even a microscopic chip can scatter the light needed to operate the sensor, and owners of such devices are advised to use special protective glass labeled "Fingerprint Friendly" or "UV Glass".
Why are cheap glasses killing the scanner?
Cases can also interfere if their sides are too high and block access to the side scanner.The finger can touch the edge of the case earlier than the sensor, which knocks the unlock algorithm.
⚠️ Attention: Hydrogel films can stretch over time and create a lens effect, distorting the image of the print. If the problem occurs after a time after the film is sticker, try replacing it.
Resetting and software update
If neither cleaning nor reconfiguring fingerprints helps, there may be software debris in the system. Check for operating system updates. Xiaomi engineers regularly release patches that fix biometric drivers.
Go to Settings → About Phone and click on the shell version. If there are no updates, try clearing the Security or Settings cache. Go to Settings → Apps → All Apps, find the one you want and select Clear Cache. Don't confuse it with Clear Data, it can reset your phone.
As a last resort, if the scanner stopped working after a specific upgrade, you may need to completely reset to factory settings.Be sure to back up the data via Mi Cloud or to your computer before doing so.
- 🔄 Check for system updates in the About Phone menu".
- 🗑️ Clear the cache of system applications responsible for security.
- 📱 Backup data before radical measures.
- 🔧 Consider rolling back on the previous firmware version (for advanced ones).
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Before resetting, try simply restarting your phone to Safe Mode, and if the scanner is working in Safe Mode, it’s a third-party application that needs to be removed.
When the scanner module needs to be replaced
There are situations where software and physical methods are powerless, where if the phone falls, falls into the water or gets very hot, the plume or the sensor module itself could fail, and in such cases hardware repairs are required.
Signs of iron malfunction: the scanner does not respond even to turn on in the settings, the phone spontaneously reboots when you try to activate the sensor, or the scanner works only under strong pressure (for side models).
Replacing the scanner in modern Xiaomi smartphones is a delicate procedure. In models with a subscreen scanner, the entire display module in the assembly often changes, since the sensor is soldered or glued to the matrix. Side scanners change more easily, but require disassembly of the body.
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If the scanner does not work even after resetting to factory settings and in safe mode, in 95% of cases it is a hardware breakdown that requires a visit to the service center.
Don't try to disassemble the phone yourself if you don't have experience. Damage to the plume or leakage can cause other components, such as the battery or motherboard, to fail.
Prevention and proper care
To keep the problem from returning, it is important to follow simple rules of operation: regularly wipe the screen and area of the scanner with a soft cloth, try not to touch the sensor with dirty or greasy hands, especially after eating or working with appliances.
Use quality accessories. Cheap security glasses are a lottery where you often lose in usability. Investing in good glass with an oleophobic coating will pay off with the comfort of daily use.
Once a month, it is helpful to remove old prints and add them again, especially if you change your phone usage conditions frequently (e.g. in winter wearing gloves, in summer with wet hands) and this will help the system adapt to the current condition of your skin.