Users of Xiaomi smartphones often face a situation when, after automatic system updates, the device begins to work unstable, quickly discharge or loses the usual functionality. Owners of the Redmi Note 9 Pro model with a memory capacity of 128 GB are no exception, and for them the question of returning to the previous, more stable version of MIUI becomes extremely urgent. This process is not without risks, but with the right approach allows you to return the gadget to the previous speed and responsiveness of the interface.
Before you start taking action, you need to clearly understand that a downgrade is a process that requires attention to detail. It is especially important to consider the presence of anti-Rollback protection, which can lock the device when you try to install an older version of the software if the current meter has already been raised. Ignoring this nuance turns the smartphone into a “brick”, which can only be restored in a service center using a programmer.
In this guide, we will take a look at all the preparation steps, tools and step-by-step algorithms. You will learn how to check the current version of the bootloader, where to find the right firmware archive and what commands to type into the console. Critically, for the Redmi Note 9 Pro with a Snapdragon 720G processor, there is a strict rollback limit only within one major version of Android, unless the bootloader is unlocked with a full reset.
Risk analysis and anti-Rollback version verification
The first step before any manipulation of system software is to diagnose the current state of the device. You need to find out which version of Anti-Rollback (ARB) is active on your Redmi Note 9 Pro. This protection is created by Xiaomi developers to prevent the installation of vulnerable versions of the software, but it also becomes the main obstacle if the user wants to roll back. If you try to flash an archive with a lower ARB value than installed in the bootloader, the process will stop, and the device may stop responding to commands.
You can check the security status through special applications from the Google Play store or by entering a secret code in dial mode. The most reliable way is to use the Device Info HW utility, which displays accurate data about hardware and software. You can also find information in the About Phone menu if you click on the build number several times, although in new versions of MIUI this option is often hidden from the average user.
⚠️ Note: If the current version of Anti-Rollback is 4 or 5, and you are trying to install firmware with the ARB 3 or lower, the phone will go into an endless reboot or hang on the Mi logo. EDL-Regime and Authorized Account.
There is a common misconception that unlocked bootloader removes all restrictions. This is not quite true: even with unlocked Bootloader, the mechanism for verifying signatures and versions of protection remains active at the low-level partition level. So before you start work, be sure to save all important data, since the rollback procedure almost always involves a complete reset of user information.
Tool preparation and firmware search
Success of the operation 90% It depends on the quality of the preparatory phase. You'll need a computer running Windows, which is a good one. USB-cable (preferably original or certified, capable of transmitting data, not just current) and a stable internet connection.The software must include Qualcomm drivers installed or ADB/Fastboot, Mi Flash Tool for Fastboot Firmware.
Finding the right firmware version is a task that requires careful attention. The archive must strictly match the model of your device: Redmi Note 9 Pro is codenamed curtana. Don’t confuse it with joyeuse (Note 9 Pro Global) or merlin (Note 9), as the firmware from another model is guaranteed to bring the phone down. XDA Developers.
☑️ Checklist of preparations
Once you download the archive, you need to unpack it. For the Recovery Firmware method, you need a file with the.zip extension. If you plan to use Fastboot mode, you need an.tgz file that you also need to unpack into the root folder of the disk so that the path to the files does not contain Cyrillic characters or spaces. This is a requirement critical for the work of the filer scripts.
Recovery method through the Recovery menu
The easiest but often blocked method is to install the old firmware through the built-in recovery menu.This method does not require a PC connection, but it only works if the Anti-Rollback version allows rollback, and you do not try to change the firmware region (for example, from Global to Chinese) without unlocking the bootloader.
To start, rename the downloaded zip archive to update.zip and place it at the root of the phone's internal memory. Then go to settings, select About Phone and click on the MIUI version. In the window that opens, click on the three dots in the upper right corner and select Select firmware file. The system will find the archive and suggest starting the update.
If the system produces an error of “failure to update” or “file corrupted”, it means that the built-in protection blocks the installation of the older version, in which case the standard path is closed, and you will have to resort to more complex methods using a PC, and this method will not work if you are trying to switch from global firmware to Chinese or vice versa, without first unlocking Bootloader.
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If the system does not see the file update.zip, Try to rename it to miui_CURTANAGlobal.zip, adding the exact file name, which can be recognized by looking at the properties of the original firmware.
Importantly, if installed successfully through Recovery, all user data will be deleted. The phone will automatically reboot and begin the initial setup process.This is normal behavior, as the data structures of different versions of Android and MIUI may not match, which requires a clean installation.
Fastboot and Mi Flash Tool
The most reliable and versatile way to roll back is to use the Fastboot mode and the official Mi Flash Tool utility. This method allows you to bypass some software restrictions and guarantees a clean installation of all system partitions. To implement it, you will definitely need an unlocked bootloader, otherwise the utility will give an authorization error.
Put your smartphone into Fastboot mode by squeezing the power and volume buttons on the device that is turned off at the same time. Connect your phone to your computer with a cable. Launch the Mi Flash Tool, press the Refresh button to let the program detect the device. In the path bar, specify the folder with the Fastboot unpacked firmware. At the bottom of the window, select Clean all mode, which is critical when downgrading.
fastboot flash recovery recovery.img
fastboot rebootAfter selecting Clean all mode, press Flash. The process will take 200 to 500 seconds. During this time, you should absolutely not turn off the cable or interrupt the power of the computer. If the process is completed successfully, the success label will appear in the Result column, and the phone will automatically restart to a new, older system.
⚠️ Note: When using the Mi Flash Tool, never select the "Clean all and lock" option if you are rolling back to an older version. MIUI. Blocking the bootloader on the old firmware can lead to a signature verification error and bootloop.
If there is a bug associated with paths or files during the firmware process, try running the utility on behalf of the administrator and moving the firmware folder closer to the root of the disk (for example, C:\rom\). Long paths with Cyrillic often cause failures when writing partitions.
Comparison of firmware methods
The choice of method depends on your skills, the state of the loader and the specific situation with the device. Below is a table that will help determine the method of rollback, assessing the risks and conditions for each option.
| Parameter | Recovery (Locally) | Fastboot (Mi Flash) | EDL (9008 Mode) |
|---|---|---|---|
| I need a PC. | No. | Yes. | Yes. |
| Unlocking BL | Desired. | I'll be sure. | Not always (depending on the account) |
| The risk of blocking | Medium. | Low (subject to the rules) | High (requires authorization) |
| Data retention | No (reset) | No (reset) | No (full reset) |
As you can see from the table, Recovery mode is suitable for simple cases when you need to roll back one version within the same region. Fastboot mode is the gold standard for enthusiasts, allowing you to fully control the process. EDL (Emergency Download) mode is used only in critical situations when the phone does not load at all, and requires an authorized Mi Account for the Redmi Note 9 Pro.
It’s also worth mentioning that using third-party tools like Xiaomi ADB/Fastboot Tools can simplify some processes, but carries additional risks. Xiaomi’s official tools are always a priority, as they ensure that all hardware modules work correctly after flashing.
What to do if the phone is stuck on the Mi logo?
Frequent mistakes and ways to solve them
Downgrade users often encounter common problems, one of the most common is the Anti-Rollback Check Failed error, which means you’re trying to install a version with a lower security number than the zeno, and the solution is two: find firmware with a current or higher ARB, or, in rare cases, wait for a new version to be reset (which is unlikely).
Another common problem is the lack of drivers in Windows. If your computer can't see your phone in Fastboot mode, you need to manually install drivers through Device Manager. Find a device with a yellow exclamation point (usually under "Other Devices" or "Android Phone"), select a driver update, and specify a path to the Qualcomm or Xiaomi driver folder.
It is also possible that the camera or fingerprint sensor will stop working after the firmware is installed, and this happens when regions are mixed (e.g., Global firmware on a Chinese machine), in which case only finding and installing stock firmware for the specific region on which the device was originally sharpened, or re-fashioning with full formatting of all partitions, helps.
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The main rule of successful rollback: the firmware version must be newer or equal to the current version of Anti-Rollback, otherwise the device will be blocked.
Remember that after returning to the old version of the system, some applications may not work properly due to changes in the Android API. It is recommended to check the operation of key functions after rollback: calls, mobile Internet, Bluetooth and geolocation.