How to set a fingerprint on Xiaomi Redmi 9: full instructions with nuances

The Xiaomi Redmi 9 fingerprint scanner is not just a way to unlock, but a complete security tool that speeds up access to the device and protects personal data from outsiders. However, many users face difficulties in the first setup: the sensor does not recognize the finger, the process is interrupted or the system emits an error. In this article, we will analyze the step-by-step instructions taking into account all the nuances of the model, and also reveal the secrets of how to make the scan as accurate and fast as possible.

The Redmi 9 has a side scanner integrated into the power button, which makes it different from the flagship models with a subscreen sensor, so the fingerprint algorithm here has its own subtleties. 3D-scanner (e.g. Mi) 10T), But when you set it up properly, it works just as reliably, and then you'll learn how to avoid the typical bugs and set the system up so that unlocking works on the first touch.

Preparing the smartphone before setting up the fingerprint

Before you start registering a fingerprint, make sure your Xiaomi Redmi 9 is ready for the procedure.Neglecting these steps often leads to crashes or low scan accuracy.

• 🔋 The battery charge is at least 30%. The registration process requires stable power supply - at low charge, the system can interrupt the settings.
• 🧼 Sensor and finger cleanliness. Fat marks, moisture or dirt on the power button distort the scan. Wipe the sensor with a dry microfiber wipe.
• 📱 Updated software. Outdated version MIUI It may contain bugs in the scanner. Check the firmware's relevance in Settings → The phone. → Updating the system.
• 🔒 Absence PIN-A fingerprint is a secondary method of unlocking, so the primary password must be set first.

Pay special attention to the choice of finger to register. The best option is the index finger of the right hand (for right-handers) or left (for left-handers), as it is most convenient for natural capture of the smartphone. Avoid registering the thumb - its position when unlocked often changes, which reduces the accuracy of recognition.

⚠️ Warning: If you have recently washed your hands or used a cream, wait 10-15 minutes before registering. Wet or oily skin can cause the sensor to “remember” the distorted print and subsequently refuse to recognize it.

Step-by-step instructions for adding a fingerprint

Now, let's get to the immediate settings, and follow the instructions carefully, because every step is important for the scanner to work properly.

1. Open Settings and go to Passwords and Security.
2. Select the fingerprint (if not, install it first). PIN-code).
3. Enter the current unlock password for confirmation.
4. Click Add Fingerprint and follow the prompts on the screen.
5. Put your finger on the power button (the sensor is located on its surface) and wait for the vibration or sound signal.
6. Raise and apply your finger again until the scale on the screen is 100% full.The system requests multiple scans to improve accuracy.
7. When completed, assign a name (e.g., “Indicative Right”) to the fingerprint and save the settings.

The key is the angle of the finger. On Redmi 9, the sensor only works when you press it tightly and perpendicularly. If you hold your finger at an angle or not press it hard enough, the system may not recognize the fingerprint. Try changing the force several times to find the optimal position.

Is recognition verified at different angles of smartphone capture?

Is the fingerprint registered under different angles (for example, when the finger is slightly bent)?

Is a backup name added for the print (e.g., "Horizontal Grab Finger")?

Did you test unlock in the dark (the sensor on Redmi 9 is not dependent on lighting, but checking will not hurt)-->

Optimizing the scanner: the secrets of accuracy

Even after successful fingerprinting, Redmi 9 users sometimes find that the sensor is unstable, it recognizes, it doesn't, and this is due to the features of the side scanner, which is less sensitive than its subscreen counterparts, and here's how to improve its performance:

• 🔄 Add the same finger twice at different angles, for example, the first time press your finger strictly perpendicular, and the second time under a slight tilt, which will increase the chances of recognition.
• 🧴 Use dry hands. If your fingers sweat frequently or you use cream, wipe them with an alcohol wipe before unlocking.
• 🔋 Turn off battery savings for security. Go to Settings → Battery → Saving charge and adding Security settings to exceptions.
• 📱 Update the sensor firmware. Sometimes the scanner is not working properly because of an outdated driver. → The phone. → Updating the system.

Another effective trick is to record your fingerprint at different temperatures, and the sensor on Redmi 9 can read your fingerprint differently depending on whether your hands are warm or cold, and try adding the same finger in winter (outdoors) and summer to help the system adapt to change.

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If the scanner stopped working after the phone fell, check the integrity of the power button. Even a slight deformation of the body can displace the sensor, making it inoperable, in which case repairs are required at the service center.

Common Mistakes and How to Avoid Them

Many users make the same mistakes when setting up a print on Redmi 9, which leads to unstable scanner performance.

• ❌ Finger application too fast. The system must have time to scan the relief, so between touches pause for 1-2 seconds.
• ❌ Using a wet finger, even a little moisture can distort the print. If your hands are wet, wipe them dry.
• ❌ Recording a print with a low battery charge can cause a process failure and incomplete template writing.
• ❌ Ignoring updates MIUI. In new versions of firmware often fix scanner bugs.

One of the most insidious mistakes is registering a fingerprint with gloves or false nails, and even if the system allows you to keep that pattern, then the recognition will be extremely unreliable. Always add a fingerprint with your bare finger, without any foreign coatings.

⚠️ Warning: If you use a security glass with a sensor cutout, make sure it doesn't close the edges of the power button. A poor-quality sticker can block part of the scanner, which will cause malfunctions.

Additional Fingerprint Features on Redmi 9

The Xiaomi Redmi 9 scanner can be used for more than just unlocking the screen, but here are some useful features that many people don’t know about:

• 🔒 Application locking. MIUI There is a built-in Application Protection feature (in the Passwords and Security section), where you can link access to individual programs (for example, banking) to your fingerprint.
• 🛒 Payment through NFC. If your Redmi 9 supports contactless payments, the fingerprint can be used to confirm transactions in Google Pay or Mi Pay.
• 📁 Hidden folders, in the conductor. MIUI You can create secure folders that are only accessible after scanning your finger.
• 🔄 Quick profile switching: If you have multiple users on your device, you can link the fingerprint to a specific profile for instant login.

An interesting feature is that you use a fingerprint to log in to games, and some apps (like PUBG Mobile or Genshin Impact) allow you to link the scan to in-game purchases or login, which is handy if you don't want to enter a password every time.

You can also use the scanner to quickly start the camera. Twice press the power button (where the sensor is located), and the camera will open immediately, even if the screen is locked. This feature is enabled in Settings → Screen Lock → Quick camera start.

Problem Solving: Scanner Fails to Work or Recognition Errors

If your fingerprint is no longer recognized or the sensor is not responding at all, use this diagnostic manual:

1. Restart the phone. Sometimes the scanner malfunctions are due to temporary system errors.
2. Remove all saved fingerprints and add them again. To do this, go to Settings → Passwords and Security → Fingerprint and click Delete.
3. Check the integrity of the power button. If it wobbles or presses poorly, the sensor may have been damaged.
4. Reset your security settings. In extreme cases, return your phone to factory settings (remember to back up!).

If the scanner stopped working after the MIUI update, try rolling back the firmware to the previous version.

1. Download the old version of MIUI for Redmi 9 from the official Xiaomi website.
2. Go to Settings → About Phone → System Update and click on the three dots in the upper right corner.
3. Select Select a firmware file and specify the downloaded archive.
4. Wait until the process is complete (the phone will reboot several times).

⚠️ Note: If the sensor is physically damaged (for example, after a fall or moisture), software methods will not help.In this case, contact the Xiaomi service center to replace the power button with an integrated scanner.

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On the Xiaomi Redmi 9, the fingerprint scanner is built into the power button, so when it malfunctions (sticks, cracks), the sensor also stops working, which is one of the most vulnerable parts of the device when mechanical damage occurs.

Redmi 9 scanner compared to other Xiaomi models

The side scanner on Redmi 9 is inferior in speed and accuracy to the subscreen sensors of flagship models (for example, Xiaomi 12 Pro or POCO F4), but has its advantages:

The Redmi 9 side scanner's main advantage is its resistance to external damage, which, unlike underscreen sensors, is not afraid of scratches on the screen and suffers less falls, but it loses speed to ultrasonic scanners (like the Mi 11), which recognize the fingerprint almost instantly.

If you use your phone often with gloves or cold temperatures, the Redmi 9 side sensor will be more reliable than the optical subscreen sensor, which can fail in cold weather, but in everyday conditions, the difference in convenience between the side and subscreen scanner is minimal.

FAQ: Answers to Frequent Questions