How to Reflash Xiaomi Mi 9: The Complete Guide

The flagship Xiaomi Mi 9, launched in 2019 with the powerful Snapdragon 855 processor, is still a device for many users. However, over time, the standard software shell may no longer meet the requirements of speed or functionality. There is a need to change the regional version of the firmware, restore the system after a failure or install a custom recovery for advanced rights.

Before you start to take action, you need to clearly understand what type of flashing you need, this can be an update to the official Global ROM, a return to factory settings through Recovery Mode or deep flashing through Fastboot mode with full memory clearing. Each method has its risks and benefits, which we will discuss in detail in this material.

It is important to note that unlocking the bootloader is a prerequisite for installing customized recoverers and informal Android builds. Official firmware can often be installed without this procedure if the region of the device coincides with the firmware region. However, to change the region from Chinese to global or European unlock is almost always necessary. We will consider all the nuances of preparation to minimize possible errors.

Preparation of the device and necessary tools

You need a computer running Windows operating system, because Fastboot drivers and firmware are the best in this environment, and virtual machines or macOS are possible, but often involve additional technical and driver compatibility issues.

Make sure to back up all your important data. During the flashing process, especially when using the Fastboot clean flag method, your smartphone’s internal memory will be fully formatted. Photos, contacts, instant messengers and files will disappear irrevocably unless you take care of them in advance. Use cloud services or transfer data to an external drive.

For the job you will need a high-quality USB-A cable, preferably original or certified, capable of transmitting data, not just charging the device, can cause system files to be interrupted, leading to critical errors. Also make sure that the battery charge of the smartphone is at least 60%, so that the device does not turn off at the most critical time.

For Xiaomi Mi 9 (codename cepheus), files are available on official resources or proven portals like XiaomiFirmwareUpdater. It is important not to confuse the version: firmware for cepheus is not suitable for Mi 9 Pro or Mi 9 SE, as they have different hardware platforms.

Unlocking the bootloader (Bootloader)

Unlocking the bootloader is the first and most important step for anyone planning to change the region of the device or install modified software. The official procedure requires filing an application through the Mi Unlock app and linking the Mi Account account to the device. After submitting an application, you must wait a certain period, which usually ranges from 7 to 15 days, depending on the current policy of the company.

The unlocking process is initiated by putting the smartphone into Fastboot mode. To do this, the device turned off must be turned on by pressing the volume button and connecting the cable to the computer. The screen will show an image of a hare in a hat-husband repairing the android, which signals the correct entry into boot mode. In this mode, the computer must determine the device as Android Bootloader Interface.

⚠️ Note: Once the bootloader is unlocked, all data on the device will be deleted for security purposes. L1 (charger HD-content in streaming services) and payment through NFC Some banks may stop working or require additional manipulation to restore the.

The unblocking tool itself uses the Mi Unlock Tool. Run the program on your PC, log in to your account and follow the instructions on the screen. If all the conditions are met (wait time has passed, the account is tied), the bootloader will be unlocked, from which point you have full control over the memory partitions, but also full responsibility for the integrity of the system.

Installation of firmware through Recovery Mode

Recovery firmware is the safest and easiest way to update or change software if the bootloader is already unlocked or if you are upgrading within the same region. There are two types of recovery: official (MIUI Recovery) and custom (TWRP), the official allows you to install only.zip (Recovery ROM) archives signed with a Xiaomi digital key, while TWRP gives you more freedom.

To install through the official recovery downloaded firmware archive must be renamed update.zip and to place it in the root of the internal memory or SD-Next, enter Restore mode by pressing the power and volume button on the device turned off. From the menu, select the language (usually available in English and Chinese), then click Wipe Data and confirm the cleanup if you go between different versions of Android or regions.

After cleaning (or without, if the update is intraregional), select Connect with MIAssistant (for PC firmware) or just Install (if the file is already in memory, although in the stock recavator, direct installation from memory is often blocked for global versions). If you use MIAssistant mode, connect the phone to your PC, run the MIUI Flash Tool (built into some versions of the firmware) or use the ADB command:

adb sideload update.zip

This method is good because it does not require complicated work with drivers of the Fastboot mode. However, it has limitations: you can not downgrade the version of Android (Anti-rollback protection) and it is difficult to switch from Chinese firmware to global without full cleaning and special manipulation of files. If the process is interrupted, the phone will most likely just reboot to Recovery mode, which allows you to try again.

Firmware via Fastboot (full cleaning)

Fastboot mode provides the deepest level of access to the smartphone file system, a method used to fully restore the device ("clean installation"), change the region from China to Global, or fix software errors that cannot be fixed through Recovery. To work, you will need to download the firmware image in.tgz format (Fastboot). ROM), Not zip.

Once you unpack the archive on your computer, you'll see a set of files and scripts. For Windows, the primary tool is the file. flash_all.bat (complete cleaning) or flash_all_except_data_storage.bat (save data, but this can cause instability when changing regions.Be sure before starting the phone is in Fastboot mode (clamped volume button when connecting the cable) and the drivers are installed correctly.

Script launch flash_all.bat It initiates a sequential recording of all the partitions: boot, system, vendor, modem, and others. 200 before 500 At this time, the phone screen may display a logo. FASTBOOT Interrupting the process at this point is strongly discouraged, as it can lead to the "bricking" of the device.

It is important to note that there is anti-rollback protection for the Xiaomi Mi 9. If you try to flash a version of Android below the one installed in the secure anti section, the device can be locked at the bootloader level. Always check the firmware version number before downgrading.

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Using Fastboot mode is a "heavy artillery" that is guaranteed to clear all file system errors, but takes longer to prepare and install drivers than the Recovery method.

Solving common mistakes and problems

In the process of flashing Xiaomi Mi 9 users often encounter typical errors — ERROR: Can't find 'persist' or partition writing errors.This often indicates a driver problem USB damaged USB-Try using another port. USB 2.0 (Ports 3.0 sometimes cause compatibility issues with older utilities) and original cable.

Another common problem is hanging on the Mi logo (Bootloop) after the firmware. If the device reboots cyclically, try logging in to Recovery and doing Wipe Data/Factory Reset. If that doesn't help, it may have installed firmware that isn't compatible with hardware revisions of your screen or memory module. In such cases, only re-routing through Fastboot helps in the correct way.

Unlocking errors, such as Device locked after a seemingly successful procedure, are solved by checking the status in Fastboot mode. If it says Device Status: Locked, then unlocking did not pass. Make sure that the developer settings include the "Factory Unlock" option and the required waiting time has passed since the account was attached.

⚠️ Note: If after firmware stopped working fingerprint scanner or proximity sensor, may have been damaged partition persist or modem. to restore them only with a backup from your device (EFS/NVRAM), This data is unique to each instance of the smartphone.

FAQ: Frequently Asked Questions

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Before you start the firmware process, take screenshots of all the important settings (access points, APN settings, email settings) after completely clearing the memory, it will be difficult to restore them from memory, and screenshots will speed up the configuration of the new system.