How to set up a fingerprint scanner on Xiaomi Mi 8: full instructions with tips

Xiaomi Mi 8 is the flagship smartphone of 2018, which still remains relevant thanks to the powerful hardware and support for the latest versions of MIUI. One of the key features of the model was an ultrasonic fingerprint scanner built into the screen. However, many users face problems when setting it up: the sensor does not respond, the system does not see the option in the menu, or the fingerprint is not saved. In this article, we will discuss all the ways to activate the scanner on the Mi 8, including hidden settings and solutions to typical errors.

Unlike the mechanical scanners on the back, the subscreen sensor on the Mi 8 requires a special approach. It works on the basis of ultrasonic waves that penetrate the display glass, so it is important to work correctly with the cleanliness of the screen, the correct position of the finger and the current version of the firmware. If you just bought a used device or updated MIUI, perhaps the scanner is disabled at the system level — it will have to be activated manually.

Before you start setting up, make sure that:

• 📱 On the smartphone installed official firmware MIUI 10 or later (on custom assemblies, the scanner may not work).
• 🔋 Battery level above 20% – when the charge is low, the system blocks the addition of new fingerprints.
• 🧼 Screen clean and dry – greasy spots or moisture interfere with scanning.
• 🔒 The device does not have a pattern lock installed or PIN-code (mandatory condition for setting up biometrics).

1. Preparation of the smartphone before setting up the scanner

Before you add a fingerprint, you have to follow a few steps, and without them, the system simply won't show you the option to customize the biometrics in the menu.

First and foremost, set the screen lock. The fingerprint scanner on the Xiaomi Mi 8 can not be the main method of unlocking: it works only in pairs with the other hand. PIN-It's a security requirement of Android, so you can't get around it:

1. Go to Settings → Password and Security → Screen Lock.
2. Choose. PIN-Password or code (pattern lock is less reliable).
3. You can come up with a combination and confirm it. Remember it or write down the code, and without it, you can't unlock your phone if the scanner fails.

Second, update the firmware. On older versions of MIUI (below 10.2), the fingerprint scanner may not work properly or even be in the settings to check whether the software is up to date:

• Open Settings → About the phone → System update.
• Click Check Updates and install the latest version available.
• If there are no updates but the MIUI version is below 12, consider the handheld firmware option via Fastboot.

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If the scanner stopped working after the update, try resetting the biometrics settings: Settings → Password and security → Fingerprints → Delete all fingerprints. Then add them again.

2. Step-by-step instructions: how to add a fingerprint

When the preparation is complete, you can start setting up the scanner. The interface may vary slightly depending on the version of MIUI, but the overall algorithm remains unchanged.

Follow this instruction:

1. Open Settings → Password and Security → Fingerprints.
2. Enter yours. PIN-proof-code.
3. Press Add Fingerprint.
4. Place your finger on the scanner area (bottom of the screen, under navigation icons). The sensor activates automatically - you don't have to press the screen.
5. Follow the on-screen tips: raise and lower your finger until the system captures all areas of the fingerprint. It is recommended to cover 100% of the area for reliability.
6. After a successful scan, assign a name (e.g., “Indicative Right”) to the fingerprint and save it.

Important: the Mi 8 scanner supports up to 5 fingerprints, you can add fingers of both hands or fingerprints of loved ones (such as a spouse), but remember that each additional fingerprint slightly increases the recognition time, the system consistently checks all the stored patterns.

Screen clean and dry |

Finger is neither wet nor dirty |

You are touching the scanner area (bottom of the display) |

No deep cuts or calluses on the finger |

The phone did not overheat (at a temperature above 40).°C sensor shuts down)-->

3. Common mistakes and their solutions

Even with the right setup, the fingerprint scanner on the Xiaomi Mi 8 can malfunction. Let’s look at the typical problems and ways to fix them.

The "failure to scan the fingerprint" error is particularly noteworthy, and it often occurs because of:

• 🩹 Skin damage on the finger (cuts, burns, severe calluses).
• 🧴 Creams or gels on your hands – they create a film that interferes with scanning.
• 🔥 Overheating of the phone - at a temperature above 40°C sensor automatically shuts down.
• 📵 Severe electromagnetic interference (e.g., near a microwave or a powerful router).

4. Hidden settings: how to speed up the scanner

By default, the fingerprint scanner on the Mi 8 is set to balance speed and accuracy, but through the developer mode, you can optimize its performance.

To activate hidden options:

1. Go to Settings. → The phone.
2. Click on MIUI Version 7 times in a row until the notification “You are a developer!” appears.
3. Return to the main settings menu and open Additional → for developers.
4. Find the Login and Security section → Fingerprint settings.

The following parameters are available here:

• 🔍 Scanner sensitivity: Increase the value if the sensor does not work well on dry or rough fingers.
• ⚡ Recognition speed: Reducing this parameter will speed up unlocking, but may lead to false positives.
• 🔄 Number of attempts: Limit to 3-5 to protect against fingerprint picking.
• 📱 Vibration in recognition: turn off if it is annoying.

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Do not set the maximum sensitivity of the scanner if you use your phone in dusty or wet conditions.

5. Alternative ways to unlock if the scanner is not working

If the fingerprint scanner on Xiaomi Mi 8 refused to work, and reboot and reset settings did not help, use alternative unlock methods:

1. Unlock through Smart Lock (if configured):

• 🏠 Trusted Places: Phone unlocks automatically at home or work.
• 📱 Trusted devices: Connecting to smartwatches or headphones unblocks.
• 👤 Facial recognition: less reliable, but works even with a damaged scanner.

To set up Smart Lock, go to Settings → Password & Security → Smart Lock.

2 Unlocking through Mi Account:

If you forgot. PIN-code, but tied the device to the Xiaomi account, you can reset the lock through the site:

1. Go to account.xiaomi.com.
2. Log in and select Find the device → Xiaomi Mi 8.
3. Click Unlock the device (only works when connected to the Internet).

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If you often forget PIN-code, enable the option to Show password when you enter in the lock settings. This will help avoid errors.

6.How to completely reset your fingerprint scanner settings

If the scanner is unstable, it can detect the fingerprint, but it can't, it can reset the scanner completely, and it can remove all the fingerprints that you've saved and return the sensor to the factory settings.

Follow the following steps:

1. Open Settings → Password and Security → Fingerprints.
2. Enter yours. PIN-code.
3. Click on the three dots in the top right corner and select Delete all fingerprints.
4. Confirm the action.
5. Reboot your phone (required!).
6. After switching on, add the prints again.

If the reset via the menu does not help, use the ADB command:

adb shell pm clear com.android.biometrics.fingerprint

This command clears the cache and the biometric module data, and then it's run.

• Reboot the phone.
• Add the prints again.
• Check the scanner in different applications (for example, for authorization in banking services).

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Resetting the scanner settings does not affect other phone data (photos, contacts, apps), but after the procedure, you will have to reconfigure all biometric parameters, including facial recognition.

7. Checking the operability of the sensor through the engineering menu

If you suspect that the fingerprint scanner on the Xiaomi Mi 8 is physically damaged, you can test it through the engineering menu. This method requires caution - do not change other parameters unless you are sure of their purpose!

Instructions:

1. Open the Phone app.
2. Enter the combination: ##4636###.
3. In the menu that appears, select Equipment Testing.
4. Scroll down and find the Fingerprint Test (or Biometric Sensor).
5. Press the Start Test and put your finger on the scanner.

Test results:

• ✅ «Pass - the sensor is good, the problem in the software part.
• ❌ «Fail: Physical malfunction of the scanner (requires repair).
• ⚠️ «No Device – the system does not detect the sensor (possibly the plume has moved away).

FAQ: Frequent questions about the fingerprint scanner on Xiaomi Mi 8