How to permanently block unknown incoming calls to Xiaomi Redmi: from built-in tools to radical methods

Unknown calls to Xiaomi Redmi have become a real scourge, with scammers, spam centers and robots attacking smartphones several times a day. According to Kaspersky, in 2023, one in three MIUI users encountered phishing calls weekly, a problem compounded by the fact that standard blocking methods (such as adding to a blacklist) often do not work – numbers are constantly changing, and carriers do not always provide effective tools.

In this article, we will discuss 5 proven ways to block unknown calls on Redmi, including hidden MIUI functions, third-party applications and operator settings. Particular attention will be paid to the method using the Do Not Disturb mode to automatically filter all unsaved contacts - it works even on budget models like Redmi 9A or Redmi Note 8 Pro. All instructions are relevant for MIUI 14 and newer, but most methods will also suit older versions of the firmware.

Why Standard Locking Doesn't Work and What to Do

The built-in blacklist in Xiaomi Redmi only blocks specific numbers that you have added manually (+79xxxxxx999), Substitute the caller’s ID or call from foreign codes (+375, +According to Roskomnadzor, 68% of spam calls in 2026 come from “grays» SIM-cards that cannot be blocked by traditional methods.

Key reasons for the inefficiency of standard tools:

• 🔄 Dynamic numbers: spammers use pools of thousands of virtual numbers that change daily.
• 📞 Caller swap ID: Fraudsters disguise real number as banking services (+74951234567) or government agencies.
• 🌍 International calls: prefixed blocking (+37) meaningless - spammers are switching to other countries.
• 🤖 Robots: Systems recognize them as ‘normal’ calls because they mimic human behavior.

The solution is a combination of built-in MIUI tools, third-party apps and operator settings, and we'll break down each method in terms of its efficiency and complexity.

Method 1: Blocking through the built-in blacklist (base level)

This method is suitable for blocking known spam numbers, and it will not protect against new calls, but will help to clear the call history from repeated scammers.

Instructions for MIUI 12-14:

1. Open the phone application (pipe icon).
2. Go to the Recent section and find the number you want to block.
3. Click on the number → select Block → Confirm the action.
4. To view blocked numbers: Settings → Lock numbers.

Limitations of the method:

• ❌ Does not block new unknown numbers.
• ❌ Maximum 500 numbers in the blacklist (on some Redmi models the limit is 200).
• ❌ Not working for hidden numbers (Unknown or Private).

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To quickly add a number to the blacklist right during the call, click the Reject button and hold it for 2 seconds - the Block option will appear.

Method 2: Do Not Disturb Mode to Filter All Unsaved Contacts

This is the most effective built-in method for blocking all unknown calls to Xiaomi Redmi without third-party apps.It allows you to automatically reset calls from numbers that are not in your phone book.

How to set up:

1. Go to Settings → Sounds and vibration → Do not disturb.
2. Activate the Do Not Disturb switch.
3. Select Allow Calls from → Only contacts.
4. Enable the option of Repeat Calls if you want to skip a second call from one number within 3 minutes (useful for emergencies).

Advantages of the method:

• ✅ Blocks all unsaved numbers, including hidden numbers (Unknown).
• ✅ It works at the system level – does not require the Internet or additional applications.
• ✅ You can configure exceptions for important numbers (e.g., delivery services).

Enable mode in settings |Select "Contacts Only" |Add exceptions for important numbers |Check work on test call-->

Important nuances:

• 📱 On the Redmi models with MIUI 13+ You can set a schedule for the mode (for example, activate it only at night).
• 🔕 Calls from blocked numbers will not be displayed in history – they are completely ignored by the system.
• ⚠️ Warning: If you are waiting for an important call from an unknown number (for example, from a courier), temporarily turn off the mode.

Method 3: Spam blocking applications (advanced level)

The built-in MIUI tools don't always cope with modern spam technologies. The third-party apps use databases of fraudulent numbers and analyze the behavior of callers in real time.

How to set up Truecaller (the most popular solution):

1. Install the app and register (you can use Google or VK).
2. Enable Phone and SMS permissions in your Android settings.
3. Go to Settings → Lock → Autolock and activate the option.
4. In the Spam section, select the categories to block: Scammers, Telemarketing, Robots.

⚠️ Note: apps like Truecaller require access to your contacts. If this is privacy-critical, use locally-locked alternatives (like Hiya offline).

Method 4: Blocking through operator settings

Russian operators provide free services to block spam, but their effectiveness varies, and the following are instructions for the main providers:

MTS

Spam Protection is able to block up to 80% of fraudulent calls.

1. Send an SMS with the text of the PROTECTION to 111.
2. Or connect in your personal account: Services → Security → Protection against spam.

Beeline

The service "Antispam" filters calls and SMS. Activation:

1. Call *110*789# and call.
2. Or in the application My Beeline: Services → Security → Antispam.

MegaFon

Spam filters block known fraudulent numbers.

1. Send. SMS 1 to 0500.
2. Or in your personal account: Services → Security → Spam filter.

Tele2.

Fraud Protection is available free of charge.

1. Call *155*1# and call.
2. Or in the app My Tele2: Services → Security.

Efficiency of operator services:

• ✅ Blocking known fraudulent numbers from Roskomnadzor databases.
• ✅ Do not require application installation or manual configuration.
• ❌ Do not protect against new numbers (delayed database updates up to 72 hours).
• ❌ Can block legitimate calls (e.g. from delivery services).

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Operator services work best when paired with built-in lock Xiaomi or third-party applications, for example, the combination of “MTS protection + Do not disturb” mode reduces the number of spam calls by 90%.

Method 5: Radical methods (for power users)

If spam calls don't stop, despite all the measures, you can use advanced methods, they require technical skills, but they give 100% results.

1. Prefix blocking via ADB

This method allows you to block entire ranges of numbers (for example, all calls from +375 or +994), requires a computer and enabled debugging over USB.

Instructions:

1. Enable Developer Mode on Redmi: Settings → About Phone → MIUI version (click 7 times).
2. Activate Debugging by USB in Settings → Additional → For developers.
3. Connect your phone to your PC and execute the command: adb shell content insert --uri content://call_log/calls --bind number:s:"+375" --bind type:i:3 (substitute +375 prefixed).
4. To block all international calls, use: adb shell settings put global block_unknown_callers 1

2. Use of Firewall (network-level lock)

Applications like NetGuard or AFWall+ can block internet access for phone services that use spammers to make VoIP calls (e.g. SIP).

⚠️ Warning: Incorrect firewall settings may disrupt standard calls.Before using, back up your data via Settings → Additionally. → Backup.

Change of IMEI (last resort)

Some scammers cling to the IMEI of the device to bypass locks.Switching the IMEI to Xiaomi Redmi is possible via the engineering menu, but:

• ⚠️ This violates the guarantee conditions.
• ⚠️ This can lead to the blocking of the operator’s network.
• ⚠️ In Russia from 2021 the change IMEI punishable by law (Article 13.3 of the Administrative Code).

If you still decide, use legal methods through Xiaomi service centers (for example, when replacing the motherboard).

What to do if the calls continue

If none of the methods worked, the problem could be deeper:

• 📱 Virus on the phone: some Trojans (e.g. Android.Spy.XXX) are replacing phone services. Check the device through Malwarebytes or Dr.Web.
• 📡 SIM-blacklisted card: If your number was previously used for spam, it could be blocked by operators. SIM-map.
• 🔄 Call forwarding: check the settings in the phone → Settings → Additionally. → Call forwarding. Turn off all rules.
• 🤖 Data Leakage: If your number has been leaked to spammer databases (for example, through leaks from websites), consider changing the number.

If you suspect a virus:

1. Install Kaspersky Mobile and perform a deep scan.
2. Check application permissions in Settings → Apps → Permissions → Phone. Remove suspicious programs.
3. Reset your phone to factory settings: Settings → About phone → Reset settings.

FAQ: Frequent questions about blocking calls on Xiaomi Redmi