How to overclock the screen Xiaomi Mi 9 to 90 Hz: safe methods and hidden settings

Xiaomi Mi 9 – flagship smartphone of 2019 with AMOLED-The 6.39-inch screen, which out of the box supports a 60Hz refresh rate. However, many users note that the device's hardware is capable of more than: Snapdragon 855 processor and graphics accelerator Adreno 640 without problems pull 90 Hz, and in some custom firmware even 120 Hz. But how to unlock this potential without the risk of “bricking” the phone?

In this article, we will discuss three working methods of overclocking the screen, including official hidden settings, ADB commands and modified firmware. Importantly, not all methods are equally safe. For example, changing parameters through engineer mode can lead to image artifacts, and incorrect firmware can lead to loss of warranty. We will describe each step in detail, indicate the possible consequences and give recommendations for rollback changes.

Before you start, check the current version of MIUI (path: Settings → About Phone → MIUI Version). At the time of writing (2026), current global and European builds support overclocking without critical bugs, but Chinese firmware (China ROM) may have problems displaying the interface.

1. Check the current screen frequency and compatibility

Before overclocking, make sure your Mi 9 does support the increased frequency. Some batches of devices (especially early revisions) had iron limits.

• 📱 Through Developer Settings: Enable Developer Mode (7 times click on Version) MIUI In Settings → About the phone, then go to Settings → Additionally. → For developers → Screen refresh rate. If you don't have an option, your firmware doesn't support overclocking out of the box".
• 🔍 Using apps: install DevCheck or CPU-Z In the Display section, see Refresh Rate. If it says 60 Hz (max), overclocking is possible.

Also check the screen model: on the Mi 9 panels from Samsung (designation E3) and BOE (designation NT36672A). The former better tolerate overclocking, the latter can show a flicker or greenish hue at 90 Hz. You can find out the manufacturer of the matrix through the AIDA64 application (section Display → Panel Manufacturer).

⚠️ Note: If your Mi 9 is purchased in China and runs on China firmware ROM without global porting, overclocking ADB This can cause a system failure, in which case it is recommended to first flash MIUI Global or Xiaomi.EU.

Method 1: Overclocking through the engineering menu (without root)

The simplest method is to activate hidden settings through the engineering menu, which does not require superuser rights, but does not work on all versions of MIUI.

1. Open the Phone app and enter the combination: ##4636##.
2. In the menu that appears, select Testing → Display Test.
3. Find the Refresh Rate and try setting 90 Hz. If the option is inactive, move on to the next method.

If the combination didn't work, try the alternative code: ##36446337## (opens EngineerMode). In this menu, go to Hardware Testing → LCD and find the Refresh Rate option. Here you can try the values of 72 Hz, 90 Hz or 120 Hz (the latter may not be supported).

Important: after changing the frequency, restart the device. If the screen starts to flicker or artifacts appear (for example, horizontal stripes when scrolling), return the value to 60 Hz and try another method.

Method 2: Overclocking through ADB (for power users)

The ADB (Android Debug Bridge) method is more versatile and works on most versions of MIUI, but requires a computer connection.

What you need:

• 💻 Computer with drivers installed ADB (You can download from the official Android website).
• 🔌 USB-cable (preferably original).
• 📱 Initiated Debugging Mode USB (developer-setting).

Step-by-step:

1. Connect the Mi 9 to your computer and open the command line (Win + R → cmd).
2. Enter the command to check the connection: Adb devices should appear serial number of your device.
3. Run the command to accelerate to 90 Hz: adb shell settings put global peak_refresh_rate 90 For 120 Hz (experimental): adb shell settings put global peak_refresh_rate 120
4. Reboot the phone.

To return the standard 60Hz, use the command:

adb shell settings put global peak_refresh_rate 60

⚠️ Attention: On some firmware MIUI 12/13 post-acceleration ADB The Auto-Refresh Rate may be missing, and to return it, follow the command: adb shell settings put global settings. auto_refresh_rate_enabled 1

Method 3: Castom firmware (maximum frequency)

If the first two methods didn't work, or if you want to get 120Hz, you'll have to resort to custom firmware.

• 📲 Xiaomi.EU: Unofficial firmware based on the MIUI, But with advanced settings, it supports 90Hz and adaptive mode.

The process of installing custom firmware includes:

1. Unlock the bootloader via the Mi Unlock Tool (can take up to 72 hours to wait).
2. TWRP Recovery installation (the version must support Mi 9, codenamed cepheus)
3. Formatting the data partition and installing firmware through TWRP.

After the firmware Xiaomi.EU frequency 90 Hz is included in the settings: Settings → Display → Screen refresh rate. In LineageOS, the path may differ: Settings → Display → Refresh rate.

* 120Hz may not work properly due to the limitations of the display driver.

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Before you run the firmware, check the kernel compatibility with your screen model. For example, the FrancoKernel r12 kernel is optimized for Samsung E3 matrices, but may not work properly with the BOE NT36672A.

Possible problems and solutions

Screen overclocking is not always a harmless procedure, and here are the most common problems and ways to fix them:

• 🔥 Overheating: With 90 The load on the processor increases by ~15-20%. If the phone is heated higher 45°C (checked in AIDA64), lower the frequency to 72 Hz or turn off overclocking in games (via Game Turbo).
• 🎨 Image artifacts: Greenish tint or stripes when scrolling are a sign of matrix incompatibility. Try another overclocking method or go back to 60Hz.
• 🔋 Increased battery consumption: when 90 Hz autonomy falls on 10-15%. To save charge, turn on the adaptive frequency (Auto-Refresh Rate) or use it. 60 Hz in energy saving mode.
• 🛑 Interface freezes: If MIUI starts to brake, clear the cache through TWRP or execute the command: adb shell pm clear com.miui.home

If the phone stopped turning on after overclocking (black screen, vibration without an image), try:

1. Press the Power + Volume Up for 10 seconds for a forced reboot.
2. If it doesn't work, flash the original kernel through Fastboot: fastboot flash boot.img fastboot reboot.

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The most stable method of overclocking is through Xiaomi.EU. It does not require root, retains the functionality of the camera and supports the use of the device. OTA-update.

6. How to return the standard settings

If the acceleration did not meet expectations or caused problems, you can return the original 60 Hz in several ways:

• 🔄 Repeat the steps from Method 1, but select 60 Hz.
• 💻 Through ADB: Adb shell settings put global settings peak_refresh_rate 60
• 🧹 Resetting settings: Go to Settings → System system → Additionally. → Resetting settings → Reset all settings (data will not be deleted, only system settings).
• 📱 Flashing: If the screen is unresponsive, run the original firmware through the Mi Flash Tool (select the Clean All option).

After returning to 60 Hz, it is recommended to:

• Check the sensor (sometimes after acceleration there are “dead zones”).
• Reset Game Turbo settings (path: Settings → Special features → Game Turbo → Reset).
• Update MIUI to the latest version (possibly, new builds have official support for 90 Hz).

FAQ: Frequent questions about overclocking the screen Xiaomi Mi 9