Modern updates to MIUI often bring not only new features, but also hidden problems, such as fast battery drain or unstable communication modules. Users of the popular Redmi 9 often face a situation when the smartphone starts to run slower after an automatic update or critical bugs appear.
The process of rolling back a version of software is technically more complicated than a regular update, and requires careful preparation of all the necessary tools. You will not only need to download the desired firmware archive, but also perform a series of preliminary actions, ignoring which can lead to locking the device, we will discuss in detail each step, from obtaining rights to the bootloader to the final installation of the system image via the computer.
It should be noted that this procedure will inevitably entail the complete removal of all user data from the internal drive. rollback of the MIUI version is possible only with a complete cleanup of memory (Clean Install), so backup photos and contacts is a mandatory first step.
Preparation of the device and necessary tools
Before you start manipulating system files, you need to make sure that you have all the required software on your personal computer. The main tool for working with Xiaomi devices in Fastboot mode is the Mi Flash Tool utility, which must be installed in the root system disk to avoid path errors. USB-A cable that can transmit data, not just charge the battery.
An important step is to choose the right firmware version, which should be strictly lower than the one installed now, but compatible with your region. Firmware archives are.tgz format for Fastboot mode, and they must be pre-unpacked to appear inside a folder with many files and a script. flash_all.bat. Up-to-date and archival versions can be downloaded on official resources or proven aggregator portals such as miui.com or xiaomirom.com.
Don’t forget to check your smartphone’s battery power, as the flashing process will not connect the device to the power grid, and the optimal charge level is above 60%, which ensures that the process is completed even if there are unforeseen delays in operation. USB-port.
⚠️ Note: Using firmware designed for other models or regions (e.g. Global on Chinese) may cause permanent damage to the software (brick.
Unlocking the Bootloader bootloader
The key to allowing firmware to roll back to an older version is an unlocked bootloader. Xiaomi's standard protections prohibit installation of software with a lower version index if the bootloader is locked, so you can't skip this step. You will need a Mi Account tied to the device and a special Mi Unlock Tool app installed on your PC to unlock it.
The process of activating the developer mode and obtaining permission to unlock can take from 7 to 168 hours, depending on the current policy of Xiaomi. Once you apply for the Settings menu → About Phone → MIUI version (you need to press 7 times on the build number) and wait in the Mi Unlock application, you can unlock that automatically erases all data.
There is a myth that unlocking a bootloader will void the warranty, but in most Xiaomi service centers this is not a reason to refuse repairs unless the physical components have been damaged. However, you should be prepared for the fact that after this procedure some banking applications and Google Pay will cease to work, although there are methods to circumvent these restrictions through Magisk.
Search and preparation of firmware archive
Finding the right version of the software is a task that requires attention to detail, since the file structure of the archives can be different. You need the archive specifically for the Fastboot mode, which is easy to distinguish by the extension of.tgz and the presence of the words "Fastboot" in the file title, as opposed to the Recovery versions with the extension.zip. After downloading the archive, it must be unpacked into the root of the C disk so that the path to the folder is short and does not contain Cyrillic characters.
For ease of navigation and understanding of which firmware to install, it is recommended to read the table compatibility and update paths. Below are examples of valid transitions for the model Redmi 9 (codename "merlin"):
| Current version | Target version (for rollback) | Transition type | Unlocking required |
|---|---|---|---|
| MIUI 12.5 (Global) | MIUI 12.0 (Global) | downgrade | Yes. |
| MIUI 12.0 (Global) | MIUI 11.0 (Global) | downgrade | Yes. |
| MIUI 12.5 (EU) | MIUI 12.5 (Global) | Change of region | Yes. |
| MIUI 12.0 (CN) | MIUI 12.0 (Global) | Change of region | Yes. |
When choosing a version, look for the lettering at the end of the title: Global stands for global, EU for European (often more optimized), and CN for Chinese, which may not have Google services built in. Installing firmware from another region also requires an unlocked bootloader and complete data cleanup, even if the MIUI version matches.
Where to find the exact version of your current firmware?
Instructions for rollback through Mi Flash Tool
After all the files are ready and the bootloader is unlocked, you can go to the direct flashing process. First, start the Mi Flash Tool on behalf of the administrator and press the Refresh button to make sure the program is ready to work. Next, you need to put the smartphone in Fastboot mode, holding the power and volume down buttons simultaneously until the Fastboot logo with the image of a rabbit appears.
☑️ Checklist before firmware
Connect the device to your computer with a cable and press the Refresh button in the program – the serial number of your Redmi should appear in the list. 9. Press the Select button and specify the path to the unpacked folder with the firmware, then select the cleaning mode at the bottom of the window. clean_all. This mode is critically important as it removes all memory partitions, preventing conflicts between the old and new versions of the system.
Press the Flash button and wait for the process to be completed, which can take 200 to 500 seconds.At this time it is strictly forbidden to turn off the cable or interrupt the computer, as this can lead to loss of boot partitions.Upon successful completion, the smartphone will automatically restart, and the first turn on can take up to 10 minutes.
⚠️ Note: If there is a Miss matching image and device error during the firmware process, this means that you are trying to install firmware for another model or region without modifying the script accordingly.
Solving errors and problems in downgrade
During the process of firmware rollback, users often encounter an “Anti-rollback check failed” error, which indicates that there is protection against downgrading the version. This protection is built into certain versions of MIUI and prohibits installation of software with a lower index, even when the bootloader is unlocked. In such cases, you need to look for an intermediate version of firmware that does not yet have this protection, or use specialized tools to reset the anti-rollback counter (which is risky).
Another common problem is the smartphone hanging on the logo. MIUI This may indicate that the firmware files are damaged during downloading or that there is an error in the recording process. USB-port (preferably) USB 2.0) and repeat the procedure by the mandatory selection of the item clean_all.
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Use USB 2.0 ports on the back of the system unit to connect your smartphone. USB 3.0 ports and hubs often trigger connection timeouts when you are running through Fastboot.
If the device goes into an endless restart (bootloop), try to enter Recovery mode (clamping the power and volume up) and perform a reset (Wipe Data). In extreme cases, when the phone does not respond to buttons, you will need to log into EDL (Emergency Download Mode) mode, which allows you to flash the device even with a completely broken bootloader, but requires an authorized Mi Account.
Initial setup after system rollback
After successfully completing the rollback procedure and first turning on, you will see a welcome screen offering to select a language and connect to Wi-Fi. Since the system has been installed clean, you will need to re-sign in to your Google and Mi Account account, as well as restore data from a previously created backup. Please note that it may take some time to restore applications depending on their number and speed of the Internet connection.
It is recommended to check the system version in settings immediately after download and make sure that the build number matches the desired one.It is also worth updating all system components through the Security or GetApps app, but beware: automatic updates may again suggest upgrading to a newer version of MIUI that you just avoided.
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After the firmware rolls back, disable the automatic MIUI update in the settings so that the system does not update itself to the problematic version again without your knowledge.
Evaluate the device's performance: interface response speed, battery life, and connection stability. If the rollback is successful, you should notice the performance improvement and the disappearance of bugs that were present in the previous version. Now your Redmi 9 is back on a stable and proven version of the software.