How to permanently disable sleep mode on Xiaomi Mi 9: 5 working ways

Why Xiaomi Mi 9 is constantly going to sleep and how to fix it

Sleep mode on the Xiaomi Mi 9 is one of the most controversial features of MIUI. On the one hand, it saves battery power by blocking background processes and limiting the operation of applications. On the other hand, it often interferes: interrupts downloads, stops music in headphones or even resets the connection with a smart watch. If your smartphone too aggressively “falls asleep” without waiting for a screen timeout, the problem lies in the settings of battery optimization or automatic memory cleaning.

In this article, we’ll look at all the ways to turn off sleep, from standard MIUI settings to hidden settings via ADB. It’s important to understand that a complete shutdown can reduce battery life by 15 to 30 percent, so we’ll also show you how to set up selective shutdown only for the right applications. If you’re using the Mi 9 as a multimedia center, for navigation or streaming, these instructions will help avoid connection breaks and lags.

Warning: Some methods require unlocking the bootloader or superuser rights. If you are a beginner, start with the safe ways (sections 2–3) and then move on to the advanced ones (sections 4–5).

Method 1: Disabling Battery Optimization for Individual Applications

The easiest and safest method is to remove the desired programs from the optimized list, which will not turn off sleep completely, but will prevent the background processes for selected applications (for example, music players or instant messengers).

Instructions:

• 📱 Open the Settings. → Annexes → Application management.
• 🔍 Select an app that should not “fall asleep” (like Spotify or Telegram).
• ⚡ Slip on the item Battery Optimization.
• 🔄 In the window open, select No Limitations.

For convenience, we have compiled a list of applications that most often require optimisation disabling:

⚠️ Attention: After update MIUI Battery optimization settings can be reset. Check them after each major update (especially when switching to a new version of Android).

Method 2: Configure screen timeout and sleep mode

If the problem is not optimization, but in too short a time before going to sleep, change the screen timeout. On the Mi 9, it is 30 seconds by default, but it can be increased to 10 minutes or turned off completely (not recommended for battery).

How to change it:

1. Go to Settings → Screen → Screen timeout.
2. Choose the maximum value of 10 minutes (or 30 minutes if available).
3. Return to Settings → Screen → Sleep Mode
4. Turn off the option Automatic transition to sleep mode.

On some firmware (e.g. MIUI 12.5+), these items may be called differently:

• 🔄 Scheduled sleep. → turn off;
• 🌙 Adaptive illumination → manually;
• 🔋 Screen energy saving → Choose High Quality.

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If the screen goes out quickly after changing the settings, check the Security app → Battery Optimization → Power Modes. Perhaps Super Power Saving mode is on, which ignores user settings.

Method 3: Disable Automatic Memory Cleanup (RAM)

Xiaomi Mi 9 aggressively clears RAM when the device is locked, which leads to the closure of background applications and simulated “sleep mode”. To avoid this, turn off automatic cleaning:

Steps:

1. Open the Settings. → The phone.
2. Tap 7 times on the MIUI version to activate the developer mode.
3. Back to Settings → Additionally. → For developers.
4. Find the option to Do Not Save Actions (or Limit Processes) and turn it off.
5. Also turn off Memory Cleanup when you lock.

After that, the applications will stay in memory longer, but note:

• ⚠️ Possible hangovers with multitasking;
• 🔋 Increase battery consumption by 5-10%;
• 📱 The phone can get hot when used intensively.

Battery charge > 50%|Backup of important data is made|Background tasks (antivirus, cleaners) are disabled)|Processor temperature (not higher than 40)°C)-->

Method 4: Using ADB to Deeply Shut Down Sleep Mode

If standard methods don’t work, you’ll need to use Android Debug Bridge (ADB), which allows you to turn off sleep mode at the system level, but requires a PC connection and basic command line knowledge.

Step-by-step:

1. Download ADB Tools and unpack the archive.
2. On your phone, activate Debugging over USB in Settings → For developers.
3. Connect the Mi 9 to your PC and run the cmd in the folder with ADB.
4. Enter the command to check the connection: adb devices must appear serial number of the device.
5. Execute the optimisation disable command for all applications: adb shell dumpsys deviceidle force-idle
6. To turn off Doze Mode (deep sleep mode) use: adb shell settings put global device_provisioned 1 adb shell dumpsys deviceidle disable

Once these commands are executed, the sleep mode will be turned off completely, but this can lead to accelerated battery discharge (up to 20% per night in standby mode).

adb shell dumpsys deviceidle enable

⚠️ Note: Some banking applications (e.g., SberBank Online or Tinkoff) may block devices with Doze Mode disabled as “hacked.

Method 5: Third-party applications for sleep control

If you don't want to dig into settings or use ADB, install one of the specialized apps that lets you flexibly adjust your phone's sleep behavior without rooting permissions.

Top.-3 applications for Xiaomi Mi 9:

• 🛠️ Greenify – suspends unwanted apps but leaves selected ones to work; supports Boost Mode to ignore optimization.
• ⚡ Battery Optimizer (by Xiaomi) – Xiaomi’s official application for fine-tuning power consumption (available in all regions).
• 🔄 Don’t Kill My App! – Shows you which apps are killing the system and helps you whitelist them.

Example of setting up Greenify:

1. Install the app from Google Play.
2. Grant Special Access rights (in Android settings).
3. Add the required apps to the Ignored List.
4. Activate Boost Mode in the application settings.

Advantages of third-party applications:

• ✅ No need to root-right;
• ✅ Flexible settings for each application;
• ✅ Possibility of rollback of changes.

Disadvantages:

• ❌ They may conflict with MIUI Optimizer;
• ❌ Some functions are paid;
• ❌ Require constant work in the background (independently consume the battery).

💡

Third-party apps are the best choice for users who want to maintain a balance between autonomy and performance, and they allow you to turn off sleep mode only for critical tasks without affecting system processes.

Frequent mistakes and their solutions

Even after the sleep mode is turned off, Xiaomi Mi 9 users face problems, and let’s look at typical situations and how to fix them.

Problem 1: The phone still “falls asleep” in 1-2 minutes.

• 🔹 Check the screen settings → Sleep regimen → Sleep schedule (possibly automatic time-out enabled).
• 🔹 Remove “optimizer” applications (for example, DU Battery Saver or Clean Master, which can override system settings.

Problem 2: After the sleep mode is turned off, the phone gets very warm.

• 🔹 Disable Do not save actions in the developer settings (see Method 3).
• 🔹 Set a limit FPS for games Settings → Special facilities → Optimizing games.

Problem 3: Notifications in messengers do not work.

• 🔹 Enable Auto-Run for the application in Settings → Annexes → Autostart control.
• 🔹 Check the Battery Optimization settings (see Method 1).
• 🔹 Update the application to the latest version (older versions may have bugs with work in the background).

Problem 4: After the MIUI update, all settings reset.

• 🔹 Make a backup of settings through Settings → Additionally. → Backup.
• 🔹 Use Xiaomi. ADB/Fastboot Tools for Automatic Application of Commands After Updating.

FAQ: Answers to Frequent Questions