How to permanently block calls from unknown numbers on Xiaomi Redmi 7: from built-in tools to secret MIUI chips

Why Calls From Unknown Numbers Are a Problem for Redmi 7 Owners

Spam calls and fraudulent numbers are one of the most annoying issues for Xiaomi Redmi users 7, base-worker MIUI 10-12 (Android 9 According to the Truecaller study, 2023 The owners of budget smartphones Xiaomi receive on the year 37% More spam calls than flagship models, and the reason is because of the firmware: default. MIUI Does not block numbers with a caller mask ID (for example, "+7495*"), crooked.

To make matters worse, Redmi 7 hasn’t received an official update to Android 11+, where Google has introduced improved spam protection through Google Phone services. However, even without a system upgrade, there are effective ways to combat it, from hidden MIUI settings to third-party apps with a database of fraudulent numbers. In this article, 5 proven methods that work on Redmi 7 regardless of the firmware version.

It's important to understand that locking unknown numbers is not just a matter of comfort, it's also a matter of security. According to Kaspersky Lab, in 2026, 43 percent of fraudulent schemes start with a switched number, so the security setting should be comprehensive.

Method 1: Built-in lock in the "Phone" application

The easiest method is to use standard MIUI tools. Unlike the “bare” Android, Xiaomi firmware has advanced lock settings, but they are hidden in non-obvious menus.

To activate the filtration:

1. Open the phone application (pipe icon).
2. Slip on three dots in the upper right corner → select Settings.
3. Go to the section "Blocking numbers".
4. Activate the switch to Lock Unknown Numbers.
5. Additionally, enable the Spam Filter option (using Xiaomi’s database).

Limitations of the method:

• ⚠️ Does not block numbers with a changed caller ID (For example, “Bank of Russia").
• ⚠️ Xiaomi spam number database is updated once in a while 2-3 weekdays.
• ⚠️ Can miss calls from international numbers (+375, +372 etc.).

To increase protection, it is recommended to combine this method with others, for example, to add to the blacklist the numbers that have already called:

1. Go back to the Call log.
2. Press your finger on the number → select Block.
3. Confirm the action (the number will be added to the blacklist automatically).

The option "Block Unknown Numbers" is enabled"|Activated "Spam filter"|Added problem numbers to blacklist|Update checked MIUI (spam-base)-->

Method 2: Use of the Security application

MIUI firmware includes the proprietary Security (shield icon) app, which has a built-in spam protection module, which is more efficient than a standard Phone, as it uses Xiaomi’s cloud database with daily updates.

Instructions for setting:

1. Open the Security app (if it isn’t on your desktop, search through search).
2. Go to the section Protection against spam (or Anti-spam in English).
3. Activate the call lock switch.
4. In the section Blocking Settings, select: ✅ Unknown numbers ✅ Spam Numbers (Xiaomi base) ✅ International numbers (optional)

Show notification of blocked calls

Advantages of this method:

• 🔹 Updated spam number database (more than 500 thousand records).
• 🔹 Possibility of geolocation lock (for example, all numbers from Belarus).
• 🔹 Integration with system notifications (shows how many calls are blocked).

💡

If the Security app does not have a Spam Protection section, update it via Google Play or reinstall the APK from Xiaomi’s official website.

Important: This module consumes additional resources (about 5-10 MB of RAM in the background). If your Redmi 7 is slowing down, check your optimization settings in Settings → Battery → Optimization.

Method 3: Third-party applications to block calls

If embedded tools MIUI They don't work, you have to look at specialized applications, and they offer advanced features like voice spam recognition, keyword blocking (like "your card is locked"), and even automatic sending. SMS-crook.

Top.-3 supplant 7:

How to install and configure (as an example of Truecaller):

1. Download the app from Google Play.
2. Register (you can register through a Google account).
3. In the settings, turn on: ✅ Blocking spam ✅ Identification of unwanted calls ✅ Showing notifications

Blacklist.

+7499*

⚠️ Note: Apps like Truecaller request access to contacts and call history. If you use Redmi 7 to handle sensitive information, consider alternatives with offline databases (e.g., Who Calls?").

Method 4: Blocking through a communications operator

Many operators offer free spam filtering services, which are effective against mass mailings but will not save fraudsters from targeted attacks.

How to connect protection to popular operators:

Features of operator lock:

• 📞 It works at the network level, it does not depend on the phone model.
• 📞 Filters up to 80% of mass spam (advertising, robbrae).
• 🚫 Does not block numbers with a changed caller ID (Fraudsters often use bank numbers).
• 🔄 Requires periodic updates of the database (once in a year) 1-2 weekdays).

To check the status of the service, send USSD-*100# (for MTS/Beeline) or *555# (for MegaFon) must be answered with a reference to "spam protection".

⚠️ Note: If you use a virtual operator (e.g. Yota, Tinkoff Mobile), there may be no locking services. 1-3.

Method 5: Hidden MIUI settings for power users

MIUI has hidden features that are not documented in the official certificate, one of which is an advanced call filter through the engineering menu.

Instructions for Redmi 7:

1. Open the Phone app.
2. Enter the combination: ##4636## (test menu opens).
3. Go to the phone information section.
4. Scroll down to the Set radio band block (don't press!).
5. Go back and select Call Blocking (could be called Call Blocking).
6. Activate options: ✅ Block unknown calls ✅ Block hidden numbers (for numbers with hidden caller) ID) ✅ Block international calls (optional)

Warnings:

• ⚠️ Do not change other options in the engineering menu – this can disrupt the network.
• ⚠️ After updating MIUI settings may reset.
• ⚠️ The method does not work on custom firmware (for example, LineageOS).

💡

Hidden MIUI settings allow you to block even numbers with a swapped caller ID that skip standard filters.

To reset the settings to factory values, enter the following in the engineering menu: ##7780## (without deleting user data).

Additional measures: how to reduce the number of spam calls

Even with the lock enabled, fraudsters can seep through the filters, and to minimize the risks, follow these guidelines:

• 🔒 Don't publish a number in the public domain. Check if it's listed on sites like this. 2GIS, Avito or social media. Use services like Google Search to find leaks.
• 📵 Turn off data transfer for spam applications. Go to Settings → Annexes → Permits → Data and limit background traffic for unknown programs.
• 🛡️ Use two-factor authentication. Fraudsters often call to get SMS-Code. 2FA Google Authenticator or Telegram.
• 📞 Turn on the recording of the conversations. MIUI There is a built-in voice recorder for calls: Settings → Recording conversations, which will help gather evidence for police in case of fraud.

If spam calls are targeted (such as being threatened or blackmailed), keep the records and contact the police. According to the Russian Interior Ministry, 68% of phone fraud cases are closed by audio recordings in 2026.

What to do if the lock is not working

If after setting up all filters spam calls continue to arrive, perform a diagnosis:

1. Check the MIUI version. Go to Settings → About Phone → MIUI version. If the version is older than MIUI 12.0.3, update the firmware through Settings → System Update.

Reset the network settings.

→ SIM-maps and mobile networks → Network reset

This will remove saved operator settings that may conflict with the lock.

Check out conflicting applications.

• Go to Settings → Permissions → Autostart.
• Turn off auto-runs for unknown apps (especially those with call rights).
• Set an alternative call. The Google Phone app has a better spam filter than the standard MIUI Dialer. Download it and make the default call in Settings → Apps → By default.

Alternative: Use Tasker to create automatic lock rules for regular expressions.