How to increase screen lighting time on Xiaomi Redmi 9: from basic settings to hidden MIUI chips

Xiaomi Redmi 9 goes out too quickly, can’t read a message or see a photo? The problem is familiar to many owners of smartphones with MIUI — by default, the system aggressively saves battery power, reducing backlight time to 15-30 seconds. But this is not a sentence: in the arsenal of Redmi 9 there are both obvious and hidden tools to adjust the screen timeout.

In this article, we will discuss all possible ways to increase the backlight time, from standard settings in the menu to editing system parameters through ADB. Particular attention will be paid to the balance between convenience and autonomy: after all, an infinitely burning display will drain the battery in a couple of hours, and also find out why after updating MIUI settings can reset, and how to prevent this.

If you need to extend the backlight time immediately, go to the first method (the easiest one), and for experienced users, common methods are prepared using the engineering menu and ADB.

Method 1: Standard MIUI settings – maximum time without root

To start with, Redmi 9 has a set-up menu that adjusts the screen backlight time, but many users don’t know that there are hidden limits that depend on the MIUI version and the firmware region.

To change the timeout:

1. Open the Settings → Display.
2. Select the "Sleep" option after (or screen timeout in newer versions of MIUI).
3. Set the desired value: from 15 seconds to 10 minutes.

But there’s a catch: some firmware has a maximum value of 5 minutes, while global versions of MIUI 12.5+ may not have a 10 minute option, and if you have one, try updating the system or using alternative methods in the following sections.

Important! After you have time, check if you reset your settings after you reboot. This is a common problem on custom firmware. If you reset, move to the ADB method.

Method 2: Developer Mode – Hidden Timeout Options

Redmi 9 has a hidden developer mode that allows you to access additional screen settings, and when you activate it, you can set the backlight time to 30 minutes (depending on the version of MIUI).

How to turn on the developer mode:

1. Go to Settings. → The phone.
2. Tap 7 times on the MIUI version (you will be notified "You became a developer!").
3. Go back to the main settings menu and open a new section for developers.

Now, find the option to Sleep when you connect to charging, where you can set a separate backlight time when the phone is charging, which is useful if you often watch videos or read by plugging your smartphone into an outlet.

Activate the mode (7 taps according to MIUI)

Check for the "Developers" item in the settings

Find the option "Sleep when connecting to charging"

Set different timeouts for battery and charging-->

⚠️ Note: In some versions MIUI 13+ If you connect to the charger, you may not be able to sleep. In this case, use the method with the engineering menu.

Method 3: ADB-commands – forced change of system parameters

If standard settings don’t work, you can manually change system settings through the Android Debug Bridge (ADB), which works without root rights, but requires connecting the smartphone to a computer.

Instructions:

1. Download and install ADB Tools on PC.
2. Turn on USB debugging in the Developer Menu on your phone.
3. Get Redmi on board. 9 To the computer and execute the command in the terminal: adb shell settings put global screen_off_timeout 600000 Here. 600000 — millisecond (10 For a minute. 30 use a minute 1800000.

Critical! Once you've run the command, restart the phone, or the changes may not apply. This method bypasses the limitations of MIUI, but it doesn't guarantee stability: once you update the system, the parameter may reset.

Method 4: Engineering menu - Advanced display settings

For power users, there is another way, the engineering menu (#4636###), which allows you to adjust not only the backlight time, but also the automatic brightness settings.

How to get into the engineering menu:

1. Open the Phone app.
2. Enter the combination: ##4636###.
3. Select the Battery Information tab (sometimes the options are hidden under other items).

In this menu, find the Screen timeout or Display timeout option. You can set up to 60 minutes, but be careful: not all options in the engineering menu are safe to change!

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Before entering the engineering menu, back up the data. Some parameters can cause the sensor or display to malfunction.

⚠️ Attention: Redmi 9 with firmware MIUI 14+ The engineering menu can be blocked. ADB-command or side of the application.

Method 5: Third-party applications - automatic backlight control

If you need flexible backlighting time management (for example, different settings for different applications), the Keep Screen On or Caffeine app will help.

• 📱 Turn off screen timeouts for selected programs (e.g. YouTube or Chrome).
• 🔄 Adjust automatic rules for the time of day or charge level.
• ⚡ Save battery, including backlighting only when used actively.

Download one of the apps from Google Play and follow the instructions, and the main advantage of this approach is that you do not need to edit system files, and the settings will be saved after the MIUI update.

Disadvantages: Some applications require special permissions (e.g., Display over other apps) that need to be manually activated in the security settings.

Comparison of methods: which way to choose?

To make it easier for you to determine, we have collected the key features of each method in the table:

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For most users, the optimal method is 1 or 2 (standard settings + developer mode). If you need flexible management, use method 5 (applications). ADB and engineering menus will only suit advanced users.

Common problems and solutions

Even after a successful setup, the backlight time may be reset or not work correctly.

Problem 1: Settings are reset after rebooting.

Solution: This is typical of custom firmware. Try:

• 🔄 Update MIUI until the last stable version.
• 📱 Use applications like Tasker to automatically apply settings after startup.
• 🖥️ Launch. ADB-flag-bearer --user 0 For forced retention: adb shell settings put --user 0 global screen_off_timeout 600000

Problem 2: There is no Screen timeout option in the engineering menu.

Solution: On newer versions of MIUI, this parameter may be hidden. Try an alternative combination:

• 📞 Enter ##6484## to access the display tests.
• 🔍 Look for options related to Sleep or Display.

⚠️ Attention: Redmi 9 with firmware MIUI 14 and later, some of the engineering codes can be disabled by the manufacturer. ADB third-party.

FAQ: Frequent questions about the time of lighting on Redmi 9