Biometrics Limits: How many fingerprints can be put into Xiaomi

The question of how many fingerprints can be put into Xiaomi is often raised by users who want to ensure the maximum security of their device or simply look for convenience in everyday use.The Chinese giant’s modern smartphones, powered by MIUI shells or the new HyperOS, offer flexible biometrics management tools, but they are not without technical limitations. Understanding these limits is critical to properly configuring the gadget, especially if you plan to use it in a corporate environment or share access with family members.

The standard and most common answer is that you can save up to 5 different fingerprints at a time, a figure that is fixed in most models, from the budget Redmi series to the flagship Mi and Xiaomi, and dictated by the security architecture used in Qualcomm and MediaTek processors.

In this article, we will discuss the technical aspects of the fingerprint module, how to circumvent constraints (where possible), and answer related questions about the reliability of biometric protection, how to properly manage stored data and why the system sometimes refuses to accept new samples.

Standard Android and MIUI system limitations

The Android operating system that underpins MIUI imposes basic limits on the number of biometric profiles stored, and it’s done for a reason: each print takes up a place in a TEE (Trusted Execution Environment) protected partition that’s isolated from the main system. Google and Xiaomi engineers have set a limit of 5 profiles as the optimal balance between user convenience and security of the encryption key storage.

When you try to add a sixth print, the system will give you an error or suggest removing one of the existing ones, which is the behavior of 99 percent of the devices on the market. It's important to understand that biometric data is not stored as normal images, but is a complex mathematical hash sum, and overflowing the buffer in the TEE can cause a security module to malfunction.

However, in some custom builds or on devices with root rights, you can find modifications that allow you to increase this limit, but for a standard user using official firmware, the 5-finger barrier is a rigid restriction.

Technical nuances of the fingerprint scanner

Modern Xiaomi smartphones use two main types of scanners: capacitive (located on the back or side in the on button) and optical/ultrasonic (embedded in the screen). Each has its own reading features. Capacitive scanners, such as the Redmi Note series, require clear physical contact and create an electrostatic field by reading the pattern of papillary lines.

The optical scanners under the screen that are found in flagships work on the principle of photographing a backlit finger. The image processing system in such modules must be very fast, so as not to delay unlocking. It is the complexity of the compression and encryption algorithms of this data that dictates the limit on the number of profiles stored.

⚠️ Note: When you add a fingerprint, try to touch the scanner with different parts of the finger pad. The system creates an average profile, and if you put your finger at too exotic an angle, unlocking may not work.

Also, consider that reading quality can be degraded by having a screen protector or contaminating the scanner. In such cases, users often try to add the same finger twice under different names (e.g., "Finger 1" and "Finger 1 copy") to increase the likelihood of successful unlocking. This is a valid method, but it consumes one of the 5 available slots.

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If the scanner is not good at reading the fingerprint, don't rush to delete it.Try simply adding the same finger again as a new profile - this often solves the problem with certain angles of inclination.

Practical application: who to add to the list

Given the 5 profile limit, it is important to distribute access rationally, and users tend to make thumbprints of both hands, as they are the ones most convenient to unlock the phone in a horizontal position (for example, when watching videos or playing games), this takes 2 slots out of 5.

The remaining 3 slots can be used for the following purposes:

• 👆 Index finger – convenient if the phone is on the table and you take it from the top.
• 👨‍👩‍👧 Family members – some parents add fingerprints to their children for quick access to emergency calls or certain apps, although this reduces the overall level of security.
• 🎭 Alternative profile – a copy of the main finger with a different name in case the main hash is damaged or stops reading after the software update.

Don’t add prints from random people or colleagues for the sake of a joke. Remember that biometrics in Xiaomi is used not only to unlock the screen, but also to confirm payments in Google Pay (or its analogues), authorization in banking applications and access to encrypted folders in the built-in file manager.

Instructions: How to manage fingerprint profiles

To add or delete fingerprints, you need to go to the security settings. The path may vary slightly depending on the version of MIUI, but the logic remains the same. First, open the Settings app and find the Passwords and Security section.

Next, select "Unlock by fingerprint." The system will request your numerical input. PIN-This is a mandatory security measure to prevent unauthorized persons from changing biometric data. In the menu that opens, you will see a list of all the added fingerprints (for example, "Fingerprint 1", "Fingerprint 2").

To remove the old profile and make room for the new one:

1. Click on the profile name you want to delete.
2. In the window that opens, select the “Delete” option (usually a basket icon).
3. Confirm the action by entering the unlock password.

After that, the slot will be freed up, and you can add a new finger by pressing the "Add fingerprint" button, and the system will guide you through the standard scanning process, where you will need to apply your finger several times to the sensor.

Comparison of protection methods in Xiaomi

Fingerprint is not the only biometric method in Xiaomi’s arsenal, and many models support face ID and traditional passwords, and understanding the differences between them will help you choose the best security configuration.

As the table shows, fingerprint remains the gold standard of balance between convenience and protection.Face unlock in most Xiaomi smartphones (except for the top flagships with the most powerful smartphone.) 3D-Scanners that are rarely used 2D-This makes it less secure for financial data protection.

⚠️ Note: Do not use simple numerical combinations (1234, 0000) as a backup password.If an attacker gains access to the phone when the owner's finger unlocks the screen (for example, while asleep), the complex password will become the only barrier.

Problems with recognition and their solution

Sometimes users are faced with a situation where the phone no longer recognizes the previously stored fingerprint, this can be due to damage to the skin of the finger, contamination of the scanner or software failure.

If the problem persists, it makes sense to delete the old profile and re-write your finger. When re-write, use the "Advanced Record" feature (if available in your version of MIUI), which allows you to add additional finger angles, which significantly increases the success rate of unlocks.

It is also worth checking whether the "High Sensitivity" mode (relevant to protective glasses) is on, which sometimes causes noise in the reading if the glass is too thick or poor quality.

Security of biometric data

It’s important to understand where your fingerprints go. In Xiaomi smartphones, data is stored in an isolated security chip and never transferred to the company’s servers or the cloud without your explicit consent, which ensures that even if you hack your Mi Cloud account, your biometric profiles remain secure inside the device.

But there are risks associated with physical access, and if the phone is in the hands of an attacker and you just unlocked it, they can open the banking application, so critical transactions (transactions, logging in to government services) always require reconfirmation or password entry.

Using two-factor authentication in conjunction with your fingerprint creates a robust shield. Never add fingerprints to people you don't trust to access your personal photos and correspondence.

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The maximum limit of 5 prints is a hardware security limitation that cannot be circumvented by standard means, and it is designed to protect the security of the device. TEE-overloading and vulnerability.

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