Locking the screen during a call on Xiaomi Redmi 9: 5 working methods

Xiaomi Redmi 9 smartphones remain popular due to the balance of price and functionality, but many users face the inconvenience of accidentally pressing the screen with their cheek or ear during a phone conversation, which leads to the on- speakerphone, switching to another contact or even completing a call.

In this article, we will discuss all available ways to lock the screen when calling Redmi 9 – from the standard settings. MIUI You will learn how to get rid of random clicks forever without losing the ease of call management. MIUI, which affect the availability of certain options.

Why is the screen not automatically locked when you call?

In most modern smartphones, the screen turns off when you lift it to your ear thanks to the proximity sensor, but on the Xiaomi Redmi 9 (and other models of the series), this feature may not work correctly for several reasons:

• 🔹 Sensor contamination – dust or greasy traces on the top panel of the device interfere with the correct operation of the sensor.
• 🔹 Damaged glass or film – if the protective coating covers the sensor area, it will no longer recognize the approach.
• 🔹 Programmatic limitations MIUI — In some versions of the firmware, the automatic lock function is disabled by default.
• 🔹 Application Conflict – Third-party launchers or gesture control programs may overlap standard settings.

Before you set the lock manually, check the sensor.

1. Open the Phone app and dial ##6484## (test code to check sensors).
2. Raise your hand to the top of the screen – the Proximity sensor should change from 5.00 to 0.00.
3. If the sensor doesn't respond, clean it with a soft napkin or reset your phone's settings.

Method 1: Enabling locking through MIUI settings

The easiest way to do this is to activate the built-in lock-in feature during a conversation, which is available in most versions of MIUI, but the path to it may vary depending on the regional firmware.

Instructions for Redmi 9 with global MIUI 12/13:

1. Open Settings → Applications → Application Management.
2. Find your phone in the list and tap it.
3. Select Permissions → Additional authorizations.
4. Activate the screen lock switch during a call (or Lock screen during calls in English version).

If this is not the case, try an alternative route:

• 📱 Settings → System and device → Additional settings → Special facilities → Locking the screen when calling.
• 📱 In some firmware, the option is hidden in the phone settings → Call settings → Additionally.

The proximity sensor is clean and not closed with film

The phone has been updated to the latest version of MIUI

No active VPN or developer mode

Reset the settings of the application "Phone" (if previously changed)-->

⚠️ Note: On the Chinese versions MIUI (For example, Redmi 9 China ROM) This parameter may not be available. In this case, use the 3-5 methods in this article.

Method 2: Use the "Lift to Lock" gesture

MIUI offers a unique Lift to Lock feature that locks the screen when you hold the phone to your ear, but it's not stable by default, to optimize it:

Adjustment steps:

1. Go to Settings → Lock screen → Additional settings.
2. Find the option to raise to lock and turn it on.
3. Return to Settings → Special Options → Physical buttons.
4. Turn off the Power button to avoid gesture conflict.

The screen will then be locked when:

• 📞 Bringing the phone to the ear (approximation sensor) + gesture).
• 🔒 Inclination of the device at an angle >45° (gyroscope).
• 🖐️ Double-click on the screen (if the option is enabled in the screen settings).

💡

If the proximity sensor is unstable, try calibrating it through the engineering menu: dial ##6484##, select Proximity Sensor and follow the instructions on the screen.

Method 3: Applications for forced blocking

If the standard settings don't help, install a third-party app.The best options for Redmi 9 are:

• 🔐 Call Lock – locks the screen when outgoing / incoming calls, supports a white list of contacts.
• 📱 Proximity Screen Off – uses a proximity sensor to lock instantly.
• 🛡️ Gravity Screen – locks the screen when you change your phone’s position (for example, when you put it in your pocket).

Instructions for setting up Call Lock:

1. Download the app from Google Play.
2. Open it and grant permissions to Read the telephone status and Draw over other windows.
3. Turn on the options: 🔘 Lock on incoming calls (blocking incoming calls). 🔘 Lock on outgoing calls (blocking when outgoing calls). 🔘 Disable power button (disable power button to complete call).

Exceptions

⚠️ Note: Some applications require special permissions for MIUI. To provide them, go to Settings. → Annexes → Application management → Three dots (menu) → Special access → Drawing on top of other applications.

Method 4: Customization through the Engineering Menu (for advanced)

If you're willing to work with hidden settings, the engineering menu allows you to fine-tune the proximity sensor and screen behavior. This method is recommended only for advanced users - incorrect changes can lead to crashes!

Step-by-step:

1. Open the Phone app and enter the code ##36446337## (or alternative ##4636## → Phone information → Perform a sensor test).
2. From the engineering menu, select Hardware Testing → Sensor → Proximity Sensor.
3. Check the current values: Value = 5 (sensor not closed). Value = 0 (sensor closed).

##6484## → Proximity Sensor → Calibrate

##36446337## → Hardware Testing → Sensor → Proximity Sensor → Set Threshold

Set the value of 3 (default 5).

After calibration, restart your phone and check the sensor in a real call. If the problem persists, return the standard settings or contact the service center - there may be a hardware malfunction.

💡

The changes in the engineering menu don't last after you reset the phone to the factory settings, and you'll have to repeat all the calibrations again.

Method 5: Alternative solutions (if nothing works)

If none of these methods worked, consider radical options:

• 🔄 Resetting phone settings: Go to Settings → The phone. → Warning: This will delete all data except files on the memory card.
• 📲 Custom firmware installation: Firmware like Pixel Experience or LineageOS have more flexible lock settings. Requires unlocking the bootloader.
• 🛠️ Hardware repair: If the proximity sensor is physically damaged, it will cost you to replace it in a service center. ~500–1000 rubles.
• 🎧 Headset usage: Connect wireless headphones (such as Xiaomi AirDots) – the screen will lock automatically when you take your phone away from your ear.

For custom firmware installation:

1. Unlock the bootloader through the Mi Unlock Tool (Mi Account is required).
2. Install TWRP Recovery for Redmi 9 (model lancelot).
3. Swipe through ADB Sideload or from a memory card.

⚠️ Warning: Unlocking the bootloader resets all data and can lead to loss of warranty.On Chinese versions of Redmi 9, you need to wait 7-15 days after you link your account.

Comparison of methods: which one to choose?

The choice of method depends on your firmware and level of technical skills. Below is a table with the pros and cons of each method:

For most Redmi 9 users, the best solution is a combination of method 1 (MIUI settings) + method 3 (Call Lock app), which ensures a reliable lock without risk to the system.

FAQ: Frequent questions