Modern smartphones provide users with many ways to protect personal data, and biometric authentication is no longer the domain of flagship devices. Owners of the popular Xiaomi Redmi 9C model can also use this feature to instantly unlock the screen and confirm payments without entering passwords. The setup process is quite simple, but requires care during the initial scan to ensure high recognition accuracy.
In this article, we will discuss in detail how to activate the sensor, what nuances should be considered to improve the read quality and what to do if the system refuses to save your data. Proper calibration will forget about the graphic keys and make using the gadget much more convenient.
It’s worth noting that the built-in scanner in this model responds to the slightest changes in the position of the finger, so it’s important to follow the system’s guidelines while learning, which ensures that the phone will recognize you even in non-standard situations, such as when you hold the device with one hand or are in low light.
Preparation for biometrics setup
Before starting the process, you need to make sure that the device has a strong digital password or pattern lock. MIUI security requires a backup login method in case the scanner can not read the fingerprint or there is a software failure. Without this step, activation of the function will not be possible.
It is also recommended to wipe the back of your smartphone and the finger you plan to use to unlock. Fat marks, dust or moisture can significantly reduce the quality of the scan and lead to errors at the initial stage.
Make sure the battery is at least 15-20% so that the device does not turn off at a critical time of data recording.Although the process does not require much power, a sudden shutdown can damage the system file storing biometric keys.
⚠️ Warning: Do not try to adjust the print if there are fresh cuts, calluses or dirt on the finger.This will lead to incorrect retention of the pattern, and in the future the phone will often make mistakes when unlocking.
If you’ve used biometrics on other Xiaomi devices before, remember that each phone saves data independently.You’ll have to go through the learning process again, as the patterns aren’t synchronized between different gadgets through your account.
☑️ Ready for scanning
Step-by-step instructions for activating the scanner
To start the setup process, go to the main menu and select Settings. In the list that opens, look for the Passwords and Security section, which is usually located at the top of the menu or in the System Apps category. This is where all access control tools are concentrated.
Inside the section, click on the Unlock by fingerprint option. The system will ask you to confirm your administrator rights by entering the previously installed one. PIN-If you have a successful authorization, you will see a welcome screen with a brief description of the features of the function.
Press the Add fingerprint button and press your finger pad tightly against the scanner located on the back of the camera. The device will vibrate and emit audible signals, suggesting that you change the position of your finger to capture different areas of the surface.
- 👆 Place your finger in the center, then move it to the edges.
- 🔄 Change the angle of inclination so that the scanner counts the side faces of the finger.
- 💧 Moisturize your finger slightly if the skin is very dry for better contact.
The process is about 10-15 When the progress lap is complete, the system will report a successful addition. 5 different fingerprints, which is convenient for unlocking the phone with different fingers or for providing access to loved ones.
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Add the same finger twice under different names (e.g., Finger 1 and Finger 1 copy) to improve the speed and accuracy of unlocking in difficult conditions.
Improvement of recognition quality
Even after a successful setup, there may be situations where the sensor doesn't work the first time, and to solve this problem, the fingerprint menu has a feature called "Add an existing fingerprint," which allows you to retrain the system by scanning the areas that were previously missed.
Select the fingerprint you already have on the list and press the enhancement button, and you will be asked to re-attach your finger, paying special attention to the upper and lower phalanxes, as well as the side rays, which is especially true if you often hold your phone with a certain grip.
It is worth considering that the skin of a person varies depending on the time of year, humidity and temperature, in winter the skin can be drier, and in summer - more wet, which requires periodic recalibration for stable work.
| Parameter | Recommendation | Impact on work |
|---|---|---|
| Dry skin | Use moisturizer | High (improves contact) |
| Pollution | Wash with an alcohol napkin | Critical (blocks reading) |
| Temperature. | Keep your hands warm in the cold | Medium (affects elasticity) |
| Repeat | Add a copy of the print | High (increases speed) |
If you wear a protective case, make sure it doesn't overlap the scanner area and doesn't have too thick sides next to it.Some thick silicone pads can shift your finger relative to the sensor, causing errors.
Using a fingerprint for payments and applications
The biometrics on Xiaomi Redmi 9C are integrated not only to unlock the screen, but also to authenticate in apps, allowing you to quickly confirm transfers in banking applications, login to social networks and purchases in digital stores.
To activate this feature, go to the fingerprint settings and find the Use of a fingerprint section, where you can put switches against the desired services, such as Google Play, Alipay or the built-in password manager.
To make payments via NFC (if the model supports) or internet banking, the bank application itself must also have a biometric login option, which is usually activated automatically when you first try to log in after you set up your phone.
⚠️ Note: When you reset your settings to factory or change your master password, all associated fingerprints are removed for security reasons.
Some apps may require re-entering a password after the device is restarted.This is normal Android security behavior that prevents unauthorized access to data if the phone has been turned off.
Deletion and management of stored data
Over time, you may need to remove your old print or replace it with a new one. Go back to the Passwords & Security menu → Unlock by fingerprint. You will see a list of all saved profiles.
Click on the name of the fingerprint to open additional options, where you can rename (for example, "Left big"), delete or re-add data, deletion occurs immediately after confirmation of the action.
If you sell a phone or transfer it to another user, be sure to delete all biometrics. Even after resetting your settings in normal mode, in some cases, the residue of data can theoretically remain in a protected memory area, although in practice, a full reset (Wipe) clears everything.
- 🗑️ Click on the fingerprint name in the list.
- ❌ Select the basket icon or the "Delete" button".
- ✅ Confirm the action of entering the password.
It is recommended to periodically check the list of active fingerprints and delete those that you no longer use, which reduces the risk of accidental unlocking and makes it easier to manage the security profile.
Where are the fingerprint data stored?
Addressing common problems
Sometimes users are faced with a situation where the scanner stops responding or is unstable, most often the problem lies in a software security failure or contamination of the sensor.
If cleaning didn't work, try restarting the device, often solving the problem of a stalled fingerprint service process, and in more complex cases, you may need to delete all your fingerprints and create new profiles from scratch.
It’s also worth checking for system updates. Xiaomi engineers regularly release patches that fix hardware drivers’ errors. Go to Settings → About phone and click on the MIUI version to check.
⚠️ Warning: If the scanner is not working even after resetting and flashing, the sensor plume or the sensor itself may be damaged.
In rare cases, the problem may be caused by established themes or third-party launchers that conflict with system lock processes.
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In 90% of cases, the problems with the fingerprint on the Xiaomi 9C are solved by re-addition of the finger with a change in the angle of inclination and thorough cleaning of the sensor.