Why Xiaomi is not blocking unknown numbers: a full analysis of the problem

You're tired of intrusive calls from unknown numbers, but your Xiaomi lockout feature stubbornly ignores them? This problem is familiar to many owners of Redmi, POCO and Mi smartphones — despite the filtering enabled, spam calls continue to leak out, and the reasons can be rooted in software failures of MIUI, and in the peculiarities of mobile operators.

In this article, we will not just list the standard tips like “reset your phone.” We will analyze in depth 7 key reasons why blocking unknown numbers may not work – from errors in the Google Dialer database to conflicts with calling apps. You will get step-by-step diagnostic instructions, alternative filtering methods and answers to questions that are not covered even in the official Xiaomi documentation.

We will pay special attention to the models MIUI 14/15 and double-devices SIM-And the cards are the ones that are most likely to have this problem. → Annexes → Calls, but zero score -- read on. We'll reveal hidden settings. MIUI, Which is not supported by Xiaomi.

1. System Application Conflict: Dialer vs Security

The main reason for the failure is because of the competition between two system applications, the standard Phone and Security, both of which try to manage blacklists in MIUI, but often do so in a non-synchronous manner, such as adding a number to the lock via Security, and Dialer simply doesn't "see" the update.

How to check:

• 📱 Open the Settings. → Annexes → Manage applications and find the phone.
• 🔍 If it's older than the version Security, conflict is guaranteed.
• 📊 Go to Settings. → The phone. → Version. MIUI. In the models with MIUI 14+ The problem is exacerbated by the separation of databases.

Decision:

1. Reset the settings of both applications through Settings → Apps → [Select App] → Storage → Clear the data.
2. Update Phone and Security through the App Store (even if there are no updates, reinstall).
3. In Security → Lock → Settings turn off the option “Sync with Dialer” (if any).

2. Google Dialer database errors

Xiaomi’s Android 11+ smartphones use Google Dialer as their primary calling app. Its spam number database is updated through Google Play Services, but often these updates are not applied because of:

• 🚫 Internet absence during synchronization.
• 🔄 Conflict with regional settings (for example, the phone is bought in China, and used in Russia).
• 📵 Google restrictions for some regions (Belarusian/Kazakhstan numbers may not be filtered).

How to fix it:

1. Go to Settings → Google → Google Services → Advertising and reset the Advertising Identifier.
2. In Settings → Applications → Google Play Services → Storage clear cache.
3. Set regional settings for the country of use: Settings → Additional → Language and input → Region.

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If the ad ID was reset, the problem was corruption in Google's database, repeat this procedure every 2-3 months.

For the POCO F5, Redmi Note 12 and later, there is a hidden option:

adb shell settings put global dialer_spam_filter_enabled 1

This command compulsorily activates spam filtering at the Android level, and requires developer rights and ADB connectivity to execute it.

3. Double-sided problems SIM-map

If your Xiaomi supports two of your SIM-Blocking unknown numbers can only work for the main card SIM. It's about architecture. MIUI, where the telephony module is tied to the primary slot, for example, on the Redmi Note 11 Pro.+ spam calls to second SIM Filtering is not done in 80% of cases.

Diagnosis:

Instructions for models with MediaTek Helio G96/G99 (e.g. POCO X5 Pro):

1. Go to Settings. → SIM-maps and mobile networks.
2. Choose the second. SIM-map and disable Volte (VoLTE).
3. In Settings → Applications → Phone → Permissions, check that the application has access to SMS and Call Log for both SIMs.

4. malfunction of Xiaomi Cloud services

The function of blocking unknown numbers in MIUI depends in part on Xiaomi Cloud, especially when it comes to synchronizing blacklists between devices. If cloud services do not work (for example, due to blocking in your country or problems with your Mi Account), then:

• 🔄 Spam Numbers database updates stop coming.
• 📱 Blacklists are not synchronized between devices.
• ⚠️ Local lock settings can be reset after rebooting.

How to check the status of Xiaomi Cloud:

1. Open your Settings → Xiaomi Account → Mi Cloud.
2. Check if the call and message sync is enabled.
3. If the sync is disabled, try turning it on and restart the phone.

⚠️ Attention: On Xiaomi models 13T redmi K60 With HyperOS, cloud lock synchronization works differently. If numbers are no longer blocked after upgrading to HyperOS, reset your Mi Cloud settings via Settings → Memory. → Backup → Cloud data dumping.

Alternative way (for advanced users):

• Install Xiaomi Cloud APK from the official source.
• Through ADB do: adb shell pm grant com.miui.cloudservice android.permission.READ_CALL_LOG adb shell pm grant com.miui.cloudservice android.permission.WRITE_CALL_LOG

5. Viruses and malicious applications

It is unlikely, but it is possible that some viruses are replacing system applications that control calls, for example, the Android.Triada Trojan (a Trojan distributed on root-righted devices) can:

• 🦠 Blocking updates to spam number database.
• 📞 Redirect calls through a proxy server.
• 🔧 Modify settings Telecom Manager (system component of Android).

Signs of infection:

• Unknown processes in Settings → Applications → Launched (e.g. com.android.phone.sec).
• Increased traffic consumption by the phone application.
• Calls go away even after the settings are completely reset.

What to do:

Install Malwarebytes and scan the system|

Check the permissions of the Phone application in Settings |

Disable the installation from unknown sources|

View the call log for suspicious numbers (e.g. +888, +999)|)

Reset your phone to factory settings (if nothing helps)

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For models with unlocked bootloader (POCO F3, Redmi K40):

1. Install Magisk and Universal SafetyNet Fix.
2. Check the integrity of system files via ADB: adb shell dumpsys package com.android.phone If the output contains lines with unknown sources - the application is replaced.

6. Hardware limitations on budget models

Not all Xiaomi smartphones are equally good at filtering spam. Budget models on Snapdragon 4xx or Helio G35/G25 processors (e.g. Redmi 9A, POCO C31) have a stripped-down telephony module.

• 📉 The spam number database is updated less frequently (once in a week). 7-10 days 1-2 days).
• 🔍 Filtering only works for numbers from your region.
• 🚫 No template lock support (for example, all prefixed numbers) +375).

Bypasses:

• 📲 Install a third-party app to lock (such as Truecaller or Hiya).
• 📞 Use the operator’s services (for example, “Antispam” from MTS or “Protection against fraudsters” from Beeline).
• 🔧 Manually add spam numbers to the blacklist through Contacts → Lockdown.

⚠️ Attention: On Redmi A1/A2 (Redmi A series of unknown number locks disabled at the firmware level, the only way out is to flash custom software (e.g. Pixel Experience) or use custom software SIM-operator-filtered card.

7 Hidden MIUI settings that support doesn't know about

There are hidden parameters in MIUI that are not documented, but affect call blocking, and can be changed through ADB or engineering menus.

List of key teams:

Enable aggressive spam filtering


adb shell settings put global spam_protection_level 3




Allow blocking by regular expressions



adb shell settings put global call_blocking_regex_enabled 1




Forced to update the spam number database



adb shell am broadcast -a android.intent.action.MASTER_CLEAR




adb shell pm clear com.google.android.dialer

For models with HyperOS (e.g. Xiaomi 14):

• 🔧 In the Engineering Menu (#4636##) select Information → Phone Information.
• 📱 Scroll to Telephony Properties and find the call.blocking option.
• 🔄 If you have a false value, change it to true).

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The most effective method for HyperOS is a combination ADB-This gives up to 95% of the blocking of spam even on problem models.

FAQ: Frequent questions about locking numbers on Xiaomi