How to make a firmware rollback on Xiaomi Redmi Note 9

Modern Xiaomi smartphones regularly receive software updates that are designed to improve stability, add new features and close security vulnerabilities. However, in practice, it often happens that the new version of MIUI is less optimized than the previous one, causing rapid battery drain or system errors. Owners of popular models such as the Redmi Note 9 often face the need to return the device to an earlier state when everything worked stable and predictable.

The rollback procedure, or downgrade, of the system is a technically complex operation that requires careful attention and understanding of the risks. With the standard means of the smartphone menu, it is impossible to return to the old version, since Xiaomi's security policy prohibits installing older versions on top of new ones. You will need to perform a number of preparatory actions, including unlocking the bootloader, which will automatically lead to the complete deletion of all data from the device.

In this article, we will discuss in detail all the steps of the procedure, the necessary tools and pitfalls that you can encounter in the process. The main rule of successful rollback is the presence of an unlocked Bootloader, without this step, further action is impossible. You should not rush to install beta versions if you are not sure of their stability, but if the problem has already occurred, follow our instructions for safe return of the system.

Risk assessment and data preparation

Before you start any manipulation of the system partition, you need to understand the responsibility. Firmware rollback is not just about installing an application, but deep processing of the structure of the operating system files. Any error in the preparation or execution stage can lead to the fact that your Redmi Note 9 will become a “brick”, that is, stop loading and responding to commands.

⚠️ Attention: The downgrade process will inevitably result in the complete deletion of all user data.Photos, contacts, correspondence and installed applications will be erased without the possibility of recovery by standard methods.

The first and most important step is to create a full backup. Don't rely on sync with the Mi Cloud or Google cloud alone, as some data, such as messenger histories or files in the Download folder, may not be copied. It's recommended to use the built-in "Mi Mover" app to transfer data to another phone or create a full backup to your computer via Fastboot mode.

It is also critical to ensure that the battery is at least 60-70% charged, ideally 100% charged, and use the original USB cable and connect the smartphone to a USB 2.0 or USB 3.0 port on the back of the computer to avoid communication breakdowns while writing system files.

Necessary tools and firmware search

To do this successfully, you'll need a specific set of software, which means that without the right tools, your computer won't see your smartphone in the right mode or be able to transfer files correctly, and the main tool will be the Mi Flash Tool, which is officially used by service centers to flash your devices.

The hardest part is finding the right firmware file. You need the Fastboot ROM version (.tgz extension) rather than the Recovery ROM (.zip extension). Also, the version you want to roll back on should be strictly lower than the one you installed now, but not too old to avoid loader version conflicts.

You should only download files from trusted sources, such as the official website miui.com or authoritative portals like XiaomiFirmwareUpdater. Using modified builds from unknown authors can lead to unstable operation of communication modules or cameras.

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When unpacking the firmware archive, make sure that the path to the folder does not contain Cyrillic characters or spaces, C:\ROM\.

Unlocking the Bootloader bootloader

A key obstacle to the old firmware is a locked bootloader. Xiaomi blocks the ability to install software that is not signed with official keys, making it impossible to downgrade without first unlocking, a process that requires linking a Mi Account account to the device and waiting for a certain deadline.

To start, activate Developer Mode. Go to Settings → About Phone and quickly click 7 times on the MIUI Version field. After the message “You are a developer” appears, go to the “Additional” → “Developers” menu and turn on “Factory Unlock” option. The system will alert you to the risks and require you to enter a password from your account.

Next, download the official Mi Unlock Tool to your computer. Launch the program, log in to your account and connect your smartphone in Fastboot mode (press the volume button when the phone is turned off and connect the cable). If done correctly, the utility will show the status of the device. Press the Unlock button.

⚠️ Warning: Once you apply for an unlock, you often need to wait 7 to 168 hours.Attempt unlocking ahead of time will cause the timer to reset and the wait will start anew.

It is worth noting that unlocking Bootloader voids the software warranty and makes it impossible to use some banking applications without additional manipulation (for example, hiding root rights or using Magisk).

Installation of drivers and preparation of PC

The computer must correctly recognize the smartphone in different modes of operation. Often the problems with firmware arise not because of errors in files, but because of the lack of the right drivers in the Windows operating system. This is especially true for older versions of the OS or fresh builds, where standard drivers may not work correctly.

It is recommended to install the universal driver package Xiaomi USB Driver. After installation, it is advisable to restart the computer. Check the Device Manager: when connecting the phone in Fastboot mode, a device called “Android Bootloader Interface” without exclamation points should appear in the list.

It is also important to disable driver digital signature verification in Windows if you are using specific debugging drivers. To do this, when you boot Windows, select Search and troubleshooting → Additional settings → Boot Options → Reboot and press F7.

Make sure there is enough free space on the system drive. Temporary files created during the firmware process can take several gigabytes. In addition, antivirus software sometimes blocks the Mi Flash Tool, so it is better to temporarily disable it or add the program to exceptions during the procedure.

The process of firmware through the Mi Flash Tool

Once you've got it all ready, you can go to the immediate rollback procedure, unpack the downloaded firmware archive (.tgz) into a separate folder, and the path to the folder should be short and not contain Russian letters, for example: C:\Xiaomi_ROM\.

Launch the Mi Flash Tool on behalf of the administrator. Press the Refresh button to detect the connected smartphone. If the device is identified, its serial number will appear in the list. Now select the firmware mode in the lower right corner of the window.

There are three main regimes:

• 🟢 Clean all – complete data cleanup and firmware installation (recommended for rollback).
• 🔵 Save user data – attempts to save data (often causes errors in downgrades).
• 🔴 Clean all and lock – cleaning and re-locking of the bootloader (dangerous when changing the region).

Select Clean all. Press Flash and wait for the process to be completed. Progress bar will show status. Do not unplug the cable or interrupt the process, even if it seems to be stalled. The whole procedure takes 200 to 600 seconds.

Solving common mistakes

Even if you follow the instructions strictly, you can experience technical failures, and one of the most common errors is Missmatching image and device, which means you’re trying to install firmware that’s designed for another region or model (e.g. Global on a Chinese device).

Another common problem is the Can not receive hello packet error, which indicates a loss of communication between the PC and the smartphone, check the cable, ports and drivers, sometimes it helps to run the program on behalf of the administrator or use another computer.

If the phone goes into an endless bootloop after firmware, the data partition may be damaged. In this case, logging into Recovery mode helps. + Power) and reset Wipe Data. If that doesn't work, you'll need to re-rout Fastboot.

⚠️ Warning: If the phone has stopped responding to buttons and is not detected by the computer even in mode EDL (Black screen, you may need special Mi-Flash account rights or hardware programmer to recover.

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The success of the rollback by 90% depends on the correctness of the selected firmware version and the quality of the product. USB-cable, not computer speed.

Frequently Asked Questions (FAQ)