Modern smartphones offer many ways to protect personal data, but biometrics remains the fastest and most convenient option. owners of the Mi 9 series flagships often face the need to quickly adjust fingerprinting immediately after buying or resetting settings. Underscreen location of the sensor in this model requires a special approach to calibration to ensure instant response.
In this article, we will discuss the process of adding a fingerprint, as well as the intricacies of the optical scanner built into the display. Proper setting will not only accelerate unlocking, but also increase the security of your banking applications and sensitive files. Ignoring simple calibration rules can lead to the fact that the device will often make mistakes or completely cease to recognize the owner.
You'll learn how to create multiple profiles for one finger, which will greatly improve the reliability of the system, and we'll also discuss how to hold your phone properly when scanning so that the angle of inclination does not affect the speed of the response, which is especially true for users who often use a smartphone with one hand or with gloves.
Preparation of the device and preliminary settings
Before starting the procedure, make sure your Xiaomi Mi 9 screen is clean and has no serious mechanical damage to the bottom of the display.Fat spots, dust or cracks in the scanner area can significantly distort the reading of the skin pattern.
It is also important to check if the current version of the MIUI operating system is installed. Developers regularly release updates that improve the algorithms for working with biometrics. Go to the settings menu and select About Phone to make sure that your software is current.
⚠️ Warning: Do not stick the protective glass too thick immediately before setting. If the glass is already glued, make sure that it has a special oleophobic layer and claimed compatibility with subscreen scanners, otherwise sensitivity may fall to a critical level.
The system will require the installation of a reliable pattern lock, PIN-If you don't have a digital key, you can't activate biometrics for security reasons. Remember this code, because you'll need it after every device reboots.
Step-by-step instructions for registration of a fingerprint
To start the process, open the main settings menu and find the Passwords and Security section. From the list of available options, select Unlock by fingerprint, after which the system will request the input of a previously installed backup password, which is the standard procedure for confirming the rights of the device administrator.
And there's an animation on the screen that tells you to put your finger on the bottom of the display. Don't press your finger too hard -- optical scanning technology reads the image, not requires physical pressure, like the old-style capacitive sensors. Easy, confident touching will be the most effective.
As you scan, the phone will vibrate to signal that you're grabbing the next section of the picture, you need to gradually change your finger position, grabbing the edges and center of the pad, and if you're usually unlocking your phone with your right thumb, register it, because that's the most natural use case.
- 👍 Put your finger on the entire surface of the pad, not just the edge.
- 🔄 Change the angle of the device in the registration process to cover different angles.
- 💧 Make sure your finger is dry and clean before starting the procedure.
- ⏱️ Make small pauses between touches so that the sensor has time to process data.
Once the progress scale is 100% complete, the system will suggest adding another fingerprint or completing the setup, and it is recommended to immediately add a second finger or duplicate the first one, which we will discuss in more detail in the next section, which will allow you to unlock the phone even if one hand is occupied or dirty.
Duplicate and expand functionality
Xiaomi’s experienced users know a secret that significantly increases the percentage of successful unlocks. Instead of registering different fingers under different numbers, you can register the same finger multiple times as a “new” fingerprint, which creates a more complete database of skin relief for a specific user.
To do this, after registering your first fingerprint, click the Add fingerprint button and use the same finger again. The system will assume that you are registering a new finger, but in fact you are only adding new angles and details to your existing profile, which is especially useful if you often hold your phone at non-standard angles.
Why do you need to duplicate a print?
Many users don’t know that the scanner compares the image entered with all the saved profiles. By adding one finger twice or three times under different names (for example, “Finger 1”, “Finger 1 copy”), you increase the probability of a match to 99%, as the system gets more variations in the image of your epidermis.> In addition to unlocking the screen, the fingerprint on the Xiaomi Mi 9 can be used for authorization in applications. Bank clients, messengers like Telegram and WhatsApp, as well as photo storage support this function. This eliminates the need to enter long passwords each time, keeping a high level of data protection in the “black” mode. When activated, the scanner is constantly running, consuming a minimum amount of power, but allowing instant access to the device with a simple touch, without pre-igniting the screen with the power button. Sensitivity settings and additional parameters In the fingerprint management menu, important settings are often hidden that affect speed and accuracy. In some versions of the MIUI firmware, the item “Improving recognition” or similar is available. Its activation causes machine learning algorithms to more actively analyze new touches and adapt to changes on the skin. It is worth paying attention to the option “Vibration when successfully unlocking the screen, although it seems to help you see the first time from the small spot or the phone when you look at the first time you see the phone from the small spot.” No vibration can create a false impression of malfunction. Parameter Recommended Impact on work Scan Mode Standard Balance of Speed and Safety Vibration Included Tactile confirmation of action Unlock in off screen Instant access without unnecessary movements Instant access Use in applications Allowed Simplification of login to banks and messengers Do not forget that over time the pattern of fingers may change due to calluses, cuts or seasonal changes in skin. In such cases, the system may begin to request a backup password more often. This is not an error, but a mechanism for protection that requires recalibulation, sometimes the solution with the current situation, the user is not being added with the print or the problem. Often, the cause is contamination of the screen or the use of a poor-quality protective film that blocks the light signal of the optical scanner. Try to remove the protective coating and check the sensor on clean glass. ⚠️ Warning: If you use cheap protective glass with a thick adhesive layer, the sensitivity of the underscreen scanner may fall on the surface. 40-50%. In such cases, only the replacement of the accessory with a specialized or re-registration of prints with the pressed glass helps. MIUI. If the problem is massive, wait for the system update, a temporary solution may be to clear the cache of the Security application or completely reset the scanner settings and then re-register. Also, external factors should be considered: bright sun directed directly into the screen can "glow" the optical sensor, making reading impossible. In such conditions, it is better to use a backup method of input or cover the screen with your hand when unlocking. The effect of environmental conditions and care Body and environment temperature also plays a role. In severe frosts, fingers can narrow, and the skin becomes drier, which worsens contact with the sensor. Conversely, in hot weather, hand sweating can create distortions. Keep this in mind when operating the Xiaomi Mi 9 in extreme conditions. To maintain high sensitivity, the filter is used regularly, it is used to reduce the dry operation of the system. 💡If your finger is wet or sweaty, slightly touch the dry fabric of your clothes or the edges of your jeans before unlocking it, which will remove the extra moisture and improve your grip on the screen. Remember that an optical scanner is essentially a miniature camera. Any obstacles in the light's path will prevent it from taking a picture of your finger, so the cleanness of the scanning area is critical to the stability of the work (FAQ) Can you unlock the Xiaomi Mi 9 with a wet finger? The optical scanners installed in the Mi 9 are extremely bad at working with wet skin. Water distorts the light flux, and the system cannot build a correct relief model. 90% of the time, unlocking will not be possible until the finger is dry. How many fingerprints can you store in your memory? Security system MIUI It allows you to store up to 5 different fingerprint profiles. That's enough to register thumbs in both hands and pointing fingers, for example, or to use duplication to improve accuracy. Why is the scanner slow after updating? After a major firmware update, the system takes time to re-index biometric data and optimize background processes. 1-2 Is it safe to use a fingerprint to pay at the bank? Yes, the fingerprint data is stored in a secure hardware module (TEE) The application of banks receive only confirmation of successful authorization, which makes this method safe for financial transactions. 💡Proper registration, taking into account different angles of inclination and screen cleanliness are the main factors of fast work of the fingerprint scanner on Xiaomi Mi 9.