How to permanently block unknown incoming numbers on Xiaomi: 5 working ways

Unknown calls from spammers, scammers and intrusive marketers have become an epidemic. According to Kaspersky, in 2023, one in three Xiaomi smartphone owners experienced fraudulent calls weekly. Fortunately, MIUI offers built-in tools to combat this problem, from a basic blacklist to advanced keyword filtering.

In this article, we will examine all available methods, from standard MIUI 12-14 functions to hidden engineering menu features and third-party applications with artificial intelligence, learn how to block not only specific numbers, but also entire ranges (for example, +375 for Belarusian spammers), as well as configure automatic detection of fraudulent calls on the basis of Google and Xiaomi Cloud.

We will focus on the hidden traps: why pin locking only works for 50 numbers, how to circumvent the limit on the number of filtering rules, and why some spammer numbers still pass. At the end of the article, an exclusive way to lock through ADB, which is not documented in Xiaomi’s official instructions.

If you're tired of calling every day with loan offers, "bank help," or silent spammers, this guide will help you set up your security in 10 minutes, and let's start with the simplest and move on to advanced methods.

1. Basic lock through the "Black List" in MIUI

The most obvious way to blacklist a number is through the standard Phone app, which works on all Xiaomi models (from Redmi Note 8 to Xiaomi 14 Ultra) and does not require root rights.

To add a number to the blacklist:

1. Open the phone application (pipe icon).
2. Go to the Journal tab and find the unwanted number.
3. Tap the number. → choose ⋮ (three-point) → Add to the blacklist.
4. Confirm the action in the pop-up window.

For manual addition:

1. In the phone app, click ⋮ → Settings → Blacklist.
2. Tap + Add a number and enter it manually (e.g. +79991234567).
3. Select the type of lock: Calls, Messages or both.

✔ Number added to the Blacklist in phone settings

✔ The type of lock is chosen correctly (calls) + SMS)

✔ In the call log, the number is marked as blocked (icon) 🚫)

✔ Checked by a test call from another phone-->

The hidden limitations of the method:

• 🔢 Limit: only 50 numbers on the blacklist (no new ones added after that).
• 📱 Does not block numbers with a changed caller ID (For example, Sberbank instead of a real number).
• 🔄 After resetting the settings, the blacklist is cleared.
• 📞 Does not work for hidden numbers (displayed as "Unknown" or "Private Number").

⚠️ Note: If you use two of these SIM-maps, blacklists apply to all cards at the same time. SIM.

2. filter spam calls through "Spam Protection"

Starting with MIUI 12, Xiaomi has integrated a cloud-based spam filtering system that analyzes incoming calls and compares them to a list of known fraudulent numbers updated daily, but by default it is disabled or running in soft mode.

To activate full protection:

1. Open Settings → Applications → Phone → Protection against spam.
2. Turn on the spam call filter switch.
3. Select the security level: Basic - blocks only confirmed spam numbers, aggressive - blocks suspicious numbers (can give false positives).

Show notification of blocked calls

How it works:

• 🤖 The algorithm analyzes the frequency of calls (if the number rings 10).+ once a day - blocked).
• 🌍 Compares to the global base of Xiaomi Cloud (updated every 6 hours).
• 📊 Uses machine learning to identify patterns (e.g., numbers with the same prefix) +7495xxx).

How to improve filtering:

1. Enable Cloud Sync in your spam protection settings, allowing Xiaomi to share spam data between users.
2. Manually add room templates (for example, +37529* to lock all Belarusian numbers).
3. Activate the option to Block Hidden Numbers (hidden in additional settings).

Every day.

Several times a week

Rarely (once a month)

Never.-->

3. Blocking of hidden and unknown numbers

Numbers that are displayed as "Unknown," "Private Number," or "Hidden Number" are some of the most intrusive. Standard methods don't block them, but MIUI has a hidden feature for that. Here's how to activate it:

Instructions for MIUI 13/14:

For MIUI 12 and older:

1. Use the engineering menu: dial the phone code ##4636##.

💡

If important calls (such as those from courier services) have stopped coming after blocking unknown numbers, add their numbers to Exceptions in phone settings. Many services use Caller ID swapping, which causes their calls to fall under the filter.

Why this method is not perfect:

• 🚨 Blocks all hidden numbers, including legitimate ones (for example, calls from Dom.ru or Mosenergosbyt).

⚠️ Note: On some firmware (Xiaomi.EU, customized) ROM) The option to block hidden numbers may not be available. ADB (section).

4. Third-party applications to block spam

If the built-in MIUI tools fail, third-party apps come to the rescue, offering advanced features such as geolocation locking, analysis of call content, integration with global spam databases (such as Truecaller or Hiya).

Top.-3 applications for Xiaomi 2026 year:

• 🛡️ Truecaller is the largest database of spam numbers (more than 500 million records), supports blocking by keywords in the name of the caller (for example, "credit", "bank.
• 🔍 Hiya, which specializes in fraudulent calls, uses algorithms. AT&T to detect fake numbers, plus: no registration required.
• 🤖 Should I Answer? — analyzes the behavior of the caller (frequency of calls, time of day). Unique feature: blocks numbers that call outside hours (at night).

How to configure Truecaller for maximum protection:

1. Download the app from Google Play and complete the registration.
2. In the settings, enable: Block spam → Aggressive mode. Detection of fraud → High level. Keyword blocking → add “credit”, “debt”, “winning”.

Blacklist

MIUI

Cloud synchronization

Comparison of annexes:

5. Advanced lock via ADB (no root)

If you’re ready to dive into the technical details, ADB (Android Debug Bridge) lets you set up a system-level lock, which works even for numbers that bypass standard filters, and has no rule-setting limit.

What you need:

• 🖥️ Computer with Windows/macOS/Linux.
• 📱 Included Debugging by USB on a smartphone (Settings) → The phone. → Version. MIUI → 7 times tap the version → return to → For developers → Debugging by USB).
• 🔗 Installed drivers Xiaomi and ADB Tools.

Step-by-step:

1. Connect the phone to the PC and confirm debugging on the smartphone screen.
2. Open the command prompt (cmd on Windows) and check the connection: adb devices must display your device’s serial number.
3. Add the number to the lock (replace). +79991234567 The actual number is adb shell content insert --uri content://call_log/calls --bind number:s:"+79991234567" --bind type:i:5 Where type:i:5 — type".
4. To block all unknown numbers, do: adb shell settings put global block_unknown_callers 1
5. Reboot your phone: adb reboot

ADB's extended teams:

• Blocking by prefix (for example, all numbers from Belarus): adb shell "echo '+375*' >> /data/user_de/0/com.android.providers.contacts/databases/contacts2.db-blocked-numbers"
• View the list of blocked numbers: adb shell content query --uri content://call_log/calls --where "type=5"
• Remove the number from the lock: adb shell content delete --uri content://call_log/calls --where "number='+79991234567' AND type=5"

💡

ADB-lock-out bypasses restriction MIUI It's 50 numbers, and it works even for hidden calls, but once you reset or update your firmware, you'll have to re-enact the rules.

⚠️ Attention: Misuse of the right ADB This can cause your phone to crash. Before experimenting, back up through Settings. → Additionally. → Backup. If the phone stops ringing after the commands, reset the network settings: adb shell am broadcast -a android.intent.action.MASTER_CLEAR

6.Blocking through the operator

Many carriers offer free spam filtering services. Unlike apps, the lock is at the network level, so spam calls don't even reach your phone, which reduces battery load and eliminates false positives.

How to connect to the main operators:

How it works:

• 📡 The operator analyzes incoming calls on its PBX before they reach your phone.
• 📊 Global databases are used (for example, from Roskomnadzor or the Bank of Russia).
• 🔄 The databases are updated daily, but with a delay in the 1-2 day-day.

Pros and cons of the method:

• ✅ Does not load the phone (filtering on the operator side).
• ✅ It works even when the smartphone is turned off (calls do not reach).
• ❌ You cannot add your numbers to the blacklist (standard databases only).
• ❌ Do not block calls via VoIP (WhatsApp, Telegram).

To improve efficiency, combine the operator service with built-in MIUI protection.

1. Activate Antispam at the operator.
2. In the phone settings, enable Spam Call Filtering at Aggressive Level.
3. Add numbers that have passed through both filters.

7. Additional measures: how to reduce the amount of spam

Even with the lock on, spam calls can leak out, and to minimize the number of spam calls, follow these guidelines:

Preventive measures:

• 🔏 Do not publish a number in the public domain (social networks, forums, ads). Use alternative methods of communication (email, Telegram).
• 📝 When registering on the sites, specify the number through temporary number services (for example, SMS-Activate).
• 🛡️ Install. VPN When using public Wi-Fi – this will make it difficult to collect your number through data leaks.
• 📱 Check regularly if your number has been leaked through Have I Been Pwned.

If the spam has already started:

• 🚫 Do not answer calls from unknown numbers – even one touch of the screen confirms that the number is “live” and spammers will call more often.
• 📞 If you pick up the phone, immediately put it down without words – voice reactions ("hello?", "Who is this?") are recorded and used to deceive.
• 🔄 Change the number if spam becomes unbearable. In Xiaomi, this can be done without data loss: Create a backup through Settings → Additionally. → Backup. Move it. SIM Restore your phone to a new phone or replace it with a carrier, except for the call and text log.