Xiaomi’s current smartphones are equipped with advanced biometric protection systems, and the Redmi Note 9 is no exception, and the scanner is integrated directly into the side button to enable quick access to the system, but users often face the need to change security settings, delete old fingerprint data or completely deactivate the fingerprint unlock function.
The reasons for this can range from the banal sale of a gadget to a new owner to problems with the sensor itself, which has begun to make mistakes or slow to react. In some cases, owners simply prefer to use a pattern lock or a digital pin code, considering them more reliable or familiar. Regardless of motivation, the process of disconnecting requires understanding the structure of the MIUI menu.
In this article, we will take a look at all the steps in managing biometric data, how to safely remove saved fingers, how to turn off scanning completely, and what to do if the system is not behaving correctly.
Why you may need to delete biometric data
Managing biometric information on a smartphone is not just a matter of convenience, but also of digital hygiene. Over time, the device can accumulate fingerprint data that you no longer use, for example, if you changed the way you wear your phone or stopped using a certain finger to unlock. Having extra entries in the scanner database can theoretically have a small impact on the speed of processing the request, although modern processors MediaTek or Qualcomm used in the Redmi Note 9, cope with this effectively.
There are also scenarios where you need to temporarily turn off the function, such as if you have damaged skin on your fingers or are in an environment where the scanner is unstable (humidity, cold), in which situations the system can be blocked after several failed attempts, requiring you to enter a password, and completely disabling the function will save you from unnecessary checks.
If you give your phone away for repair or temporarily give it to your child, deleting your biometrics is a mandatory privacy protection step. Even if you have a password, having your fingerprint on the system creates a potential vulnerability.
Step-by-step instructions for removing fingerprint
The process of removing saved fingerprints in the MIUI shell is intuitive, but requires verification of the identity of the owner. Before starting any manipulation, make sure that you know your pattern lock or digital code, as the system will definitely request it to make changes to the security settings.
First, you need to go to the main settings menu, unlock the screen and find the gear icon, then follow the path: Passwords and security, and that's where all the device access management tools, including screen time, privacy and biometrics, are concentrated.
☑️ Preparation for data deletion
In the menu that opens, select Add fingerprint or fingerprint management, depending on the firmware version. You will see a list of all registered fingers numbered as "Finger 1", "Finger 2", etc. Click on the desired one, and the system will suggest two options: rename or delete. Select the option Delete and confirm the action by entering the password.
If you want to clear all the data at once, it’s often more convenient to use the full biometrics reset feature, which is in the same menu, usually as a “Clear All” button or by removing each finger in turn, guaranteed to remove all fingerprint data from the protected area of the CPU memory.
⚠️ Note: After the fingerprint is removed, biometric unlocking will become impossible until you register a new finger or turn the function back on.
How to completely disable the scanner function
Removing specific fingerprints does not always mean completely disabling the module. In some versions of MIUI, even after removing all fingers, the system may suggest adding a new one when trying to unlock. In order to fully deactivate the possibility of using a side scanner to log in, you need to change the unlock method.
Go to Passwords and Security and find Unblock, and it shows all the methods available: facial recognition, fingerprint, password, PIN-If you delete all your fingerprints, the fingerprint method may remain active but invalid.
However, if your goal is to stop the phone from responding to the touch of the power button in the context of unlocking, it is enough to simply not have the biometric data registered. In this case, touching the button will only turn on the screen or wake the device, but not try to count the finger to enter. This saves minimal energy and eliminates random positives.
It is important to distinguish between disabling the unlock function and disabling the hardware module itself. Software methods do not completely "turn off" the physical scanner in the button, since it also acts as a normal power button, you can only prevent the system from using its data for authorization.
Impact on the battery
Configuring alternative protection methods
Once you have decided to opt out of using your fingerprint on the Redmi Note 9, it is critical to set up an alternative login method. Leave your smartphone unprotected is strongly discouraged, especially if it stores personal photos, correspondence and access to banking applications.
The most reliable option is a complex password consisting of letters and numbers, but for daily use, many users choose a pattern lock or 6-digit key. PIN-The pattern lock is convenient because it can be entered quickly without looking at the screen, thanks to muscle memory.
- 🔢 PIN-code: sequence 4-6 More reliable than a simple key"1234" date of birth.
You can configure the new method in the same password and security menu → screen lock. The system will suggest selecting the type of protection and entering it twice for confirmation. After that, the old method (if it was) will be replaced or supplemented with a new one, depending on the security policy settings.
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If you refuse biometrics, be sure to install a complex pattern lock or a long one. PIN-code to compensate for loss of convenience by faster access with increased data protection.
Typical problems and their solution
Xiaomi users sometimes face situations where the fingerprint is no longer readable or the system prevents it from being deleted, most often due to software failures of the MIUI shell or contamination of the sensor surface. Because the scanner in the Redmi Note 9 is combined with the power button, it is constantly exposed to the finger, which leads to a buildup of fat and dirt.
If the scanner is not working properly, try to wipe the side of the device with a soft napkin slightly moistened with alcohol, and the problem may lie in a protective case that covers part of the sensor or shifts the finger. Remove the case and check the function.
The table below shows common errors and ways to fix them:
| Problem. | Possible cause | Decision |
|---|---|---|
| The scanner is not responding. | Pollution or software failure | Wipe the button, reboot the phone |
| Error in removal | Wrong password | Enter the current screen lock code |
| Low reading speed | Damage to the epidermis | Add another fingerprint |
| Unblocking spontaneously | Sensor sensitivity | Retrain the fingerprint by adding the edges of the finger |
If the software methods don't work and the scanner is chaotic even after resetting, there may be a hardware malfunction, which may require replacing the plug of the power button at the service center.
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To improve reading accuracy, add the same finger twice at slightly different angles, which will create a more complete digital cast and reduce the number of recognition errors.
Resetting security settings to factory
In extreme cases, when the Redmi Note 9 security system is not working properly or you forgot the password to confirm actions in the menu, you may need to completely reset your settings.
It is important to understand that resetting security settings (not to be confused with a full phone reset) will delete all saved fingerprints, facial recognition data and passwords for second spaces. To perform this operation, go to Passwords and Security and find Reset at the bottom of the screen or in the option menu.
Once you confirm and enter your master password (if installed) or your Mi Account password, all biometrics will be permanently deleted, a useful procedure before selling the phone or transferring it to another user.
⚠️ WARNING: Full Hard Reset via Recovery Mode will also remove all fingerprints, but this is an extreme measure, as it erases all personal data, photos and contacts from the phone's internal memory.