Xiaomi Mi 9 SE comes with a MIUI shell that, despite its functionality, is often criticized for redundancy and advertising. Many users are looking for a way to replace the standard system with a pure Android to get performance, no excess software and current security patches. The process of replacing the operating system requires care, but the result is worth it.
In this article, we will go through all the steps in detail, from tool preparation to the first download in a new environment. USB-It's important to understand that any manipulation of the bootloader carries risks, so follow the algorithm of actions strictly by steps.
Before you start, make sure that your device model is indeed Xiaomi Mi 9 SE (codenamed grus). Installing firmware from other models will cause the gadget to fail. It is also worth downloading all the necessary files in advance, as the Internet on the phone will not work during the installation process.
Workplace preparation and backup
The first step is to save all the important data. The custom firmware installation process involves completely cleaning the device's internal memory. Backup of contacts, photos and documents must be done to an external drive or to the cloud storage. Once formatted, it will be impossible to restore files without a backup.
You'll need a computer running Windows, Linux or macOS. You'll need ADB and Fastboot drivers installed on your PC. You can download Platform-tools from the official Android developer site for convenience. This is a basic set of utilities for interacting with your smartphone in debugging mode.
⚠️ Before starting work, charge the battery of the device to at least 70-80%. Interrupting the firmware process due to battery discharge can lead to the inability to turn on the phone.
You also need to activate the developer mode. Go to Settings → About phone and quickly click on the MIUI build number seven times. Once you have a developer mode activation message, go to the advanced settings and enable USB debugging. Without this, the computer will not be able to transfer commands to the device.
☑️ Firmware readiness check
Unlocking the Xiaomi bootloader
The Xiaomi factory bootloader is locked and does not allow you to install third-party Recovery or firmware. To unlock it, you will need the Mi Unlock Tool utility and Mi Account. SIM-card to phone, link the device to the account in the settings menu of the Mi-account.
After the tether, you have to wait a certain time. Usually it's 7 days (168 hours), but in some cases it can be extended to 30 days. This is the company's protective mechanism. When the wait period expires, turn off the phone and turn it on in Fastboot mode, holding the Volume Down + Power buttons simultaneously.
Connect your smartphone to your PC and launch the Mi Unlock Tool. If all the conditions are met, the program will suggest unlocking the device.The process will reset all the data, so you won't need to back up again after this step if you haven't already done it. Successful unlocking is confirmed by the corresponding message on the phone screen and in the program.
What to do if Mi Unlock is writing an error?
It is important to note that after unlocking the bootloader, some features such as Widevine are available. L1 (for HD-content streaming) and payment through NFC Some banks may stop working or require additional manipulation to restore, which is a fee for the ability to install custom software.
Installation of custom Recovery TWRP
The standard recovery menu does not allow you to install modified firmware. We will need a TWRP (Team Win Recovery Project) adapted specifically for grus. Download the current.img image from a proven source, for example, from the XDA Developers forum or the official TWRP website.
Put your phone in Fastboot mode (Loud down + Power buttons) and connect to your computer. Open the command line in the folder with ADB utilities. Enter a command to check the connection:
fastboot devicesIf the serial number is displayed, the connection is established. Now you need to flash Recovery. Importantly, we will use the command fastboot boot for temporary download to immediately install the firmware, or fastboot flash for permanent recording.
fastboot boot twrp-3.x.x-x-grus.imgOnce you do that, the phone will reboot to the TWRP menu. The interface will be touch-sensitive. The first thing you need to do is allow modifications to the system partition by moving the slider at the bottom of the screen. If you don't, TWRP won't let you mount the partitions to write.
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If after installing TWRP, the phone loads again into the standard MIUI, then the system overwrote Recovery. In this case, immediately after the TWRP firmware, you need to reboot to Recovery (clamping Volume up + Power), preventing the system from starting completely.
Selection and preparation of firmware
There are many options for pure Android for Xiaomi Mi 9 SE. The most popular LineageOS, Pixel Experience (or its forks) and crDroid. LineageOS is famous for stability, Pixel Experience gives an interface like the Google Pixel, and crDroid offers ample customization options.
The downloaded firmware (.zip file) and Google Services Package (GApps) should be placed in the phone’s internal memory or on the firmware if they are not built into the firmware. SD-It's the easiest way to do this is through a map. MTP-The mode when the phone is displayed as a drive in TWRP, or to transfer files before entering the recavity.
- 📱 LineageOS is the best choice for those who appreciate minimalism and stability.
- 🎨 crDroid is suitable for users who want to customize each element of the interface.
- 🚀 Pixel Experience is perfect for fans of Google’s ecosystem and smooth animations.
Be sure to check firmware build date. Using versions older than 6 months can lead to security vulnerabilities and bugs in applications. For the Mi 9 SE with a Snapdragon 712 processor, it is important to use firmware optimized for the arm64 architecture.
Process of installation of the operating system
If you're on the TWRP menu, go to Wipe. Select Advanced Wipe and tick the Dalvik/ART Cache, System, Vendor and Data sections. Internal Storage section is not to be touched if the firmware files are there. Move the slider to start cleaning.
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A full vape (cleanup) is a must when switching from MIUI to pure Android. Trying to upgrade on top of the old system without cleaning will result in a cyclic bootloop.
Once cleaned, go back to the main menu and select Install. Find the firmware archive and click on it. Confirm the swipe installation. Wait until the process is complete. If the firmware doesn't have built-in Google services, install OpenGApps or NikGApps archives in the same way immediately without restarting.
In some cases, you need to clear the Format Data format (typing the word yes), especially if you have encrypted your device before, which completely deletes all data and removes the encryption that is necessary for the new system to work properly.
| Section | Action. | Purpose |
|---|---|---|
| Dalvik / ART | Wipe | Cleaning the compilation cache |
| System | Wipe | Removing the old MIUI |
| Data | Wipe / Format | Deletion of user data and encryption |
| Cache | Wipe | Clearing temporary files |
First start and initial setup
When the installation is complete, press the Reboot System button. The first run can take 3 to 10 minutes. Don't panic if you see the Android logo or firmware name on the black screen - the system performs initial optimization of applications.
Once you download, you will be greeted by a customizable wizard. Choose a language, connect to Wi-Fi. Since Google services are already installed (if you have been GApps), the system will prompt you to log in. Once you log in, contacts and settings will start synchronizing if you have used Google backup.
Now your Xiaomi Mi 9 SE runs on pure Android, you will notice a significant difference in RAM consumption and interface smoothness, and it is recommended to immediately go to the settings and check for security updates for the installed version of the firmware.
⚠️ Warning: Camera in custom firmware may work worse than in stock MIUI, To solve this problem, we recommend installing Google Camera (GCam), ported specifically for the Snapdragon 712 processor.
Possible problems and solutions
Even if you follow the instructions strictly, you can get complicated. One of the common problems is Bootloop. If the phone is stuck on the logo for more than 10 minutes, you need to go back to TWRP (clamping Volume Up + Power) and repeat the Format Data procedure and install the firmware again.
Another common bug is VoLTE or Wi-Fi not working, which is often due to the incorrect version of the base files (firmware).Before installing a clean Android, make sure that the phone has the latest official MIUI firmware installed, as it updates the modem and bluetooth partition.
- 🔋 Quick discharge – on the first day after installation, the system is trained to use the battery, the problem should disappear.
- 📶 No network – check if the bootloader is officially unlocked, not through workarounds.
- 📸 Fuzzy photo – install the Google Camera port, the link is usually in the forum firmware topic.
If nothing works, you can always go back to MIUI, so download the official.zip firmware, put it in TWRP, and install it, and it will bring the phone back to factory status.