How to return the old firmware on Xiaomi Redmi 9T: 3 proven ways without the risk of “bricking”

Have you upgraded the Xiaomi Redmi 9T to a new version of MIUI and encountered bugs, brakes or an unexpected battery discharge? Or perhaps the new firmware has eaten your favorite features that worked in the previous version? Running back the firmware (downgrade) is real, but the process requires caution: wrong actions can turn a smartphone into a “brick.” In this article, we will discuss three official and informal methods to return the old firmware to Redmi 9T (codename lime), including the nuances of unlocking the bootloader, choosing the correct version of MIUI and data recovery.

It's important to understand that Xiaomi doesn't always support one-click downgrade. For example, if you upgrade from MIUI 12 to MIUI 14, simply resetting your settings won't help -- you'll need manual firmware via Fastboot or Recovery. We'll detail each step, warn you against common mistakes (such as why you can't use Redmi 9 Power firmware, although they're seemingly identical), and give you a checklist to prepare the device. If you're a beginner, start with the first method (via Mi Flash Tool), experienced users can consider custom recovery using TWRP.

Why You Might Need to Reverse the Redmi 9T

According to 4PDA Forum statistics, about 30% of Redmi 9T users experience problems after MIUI updates.

• 🔋 Accelerated battery discharge: New versions MIUI Often optimized for fresh models, and for a budget Redmi 9T (Snapdragon 662 processor can add background processes that reduce the running time to 30%.
• 🐢 Lags and slowdowns: Especially noticeable in games or when multitasking. MIUI 13 Many people complain of hanging up when opening the camera.
• 📱 Disappearance of features: New versions remove useful chips – for example, Game Turbo for old models or settings DC Dimming.
• 🔒 Security bugs: Rarely, but it happens that the update breaks Google Pay or blocks unlocking in the face.
• 📡 Network problems: For example, support is missing 4G on some operators (frequent complaint after switching to the MIUI 14).

Before you start downgrade, check if the factory reset will help (in Settings → About Phone → Settings Reset). Sometimes bugs are fixed after cleaning the cache or reinstalling the applications. If the problem persists, read on.

Preparation for rollback: what to do before the firmware

Unprepared downgrade is a direct route to the bricking up of the device. Follow this checklist to minimize the risks:

Make a backup copy of the data (photos, contacts, SMS)

Check the device model in Settings → About Phone → Model (should be Redmi 9T, not Redmi 9 Power)

Make sure the battery is > 60%

Download the correct version of the firmware (see table below)

Install Xiaomi drivers on PC (from the official website)

Prepare. USB-cable (preferably original)

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Pay special attention to the choice of firmware. For Redmi 9T (codename lime), only files marked with lime in the title are suitable.

• ✅ Right: lime_global_images_V12.0.1.0.QJQMIXM_20210112.0000.00_10.0_global
• ❌ Wrong: limein_global_images... (It's for Redmi. 9 Power, code limein!)

Download the firmware only from official sources:

💡

If you downloaded firmware in.tz format (archive for Mi Flash Tool), do not unpack it manually - the program will do this automatically when you are firmware.

Method 1: Recoil through the Mi Flash Tool (official method)

This is the most reliable way, but it requires unlocking the bootloader. If you've never done this, it takes up to 7 days because of the wait. SMS-But the method is guaranteed to work and is suitable even for "brick" devices.

Step-by-step:

1. Unlock the bootloader: Link your Mi Account to your device in Settings → Xiaomi Account. Go to en.miui.com/unlock and request unlock. Download Mi Unlock Tool, connect your phone in Fastboot mode (clip Volume Down + Power) and follow the instructions.

Download the firmware.

Fastboot

.tgz

Install the Mi Flash Tool

here

Switch the device.

• Unpack the firmware in a folder without Cyrillic characters (for example, C:\lime_fastboot).
• Launch MiFlash.exe, click Select and specify the firmware folder.
• Connect your phone in Fastboot mode (a screen with a rabbit and the words Fastboot).
• At the bottom of the program, select clean all and click Flash.

Firmware time: 5-10 minutes. Once complete, the phone will automatically restart. The first start can take up to 15 minutes - don't interrupt the process!

⚠️ Note: If you are looking for a version MIUI older than the one originally established (e.g., with the MIUI 13 on MIUI 12), after a downgrade, it may be necessary to re-unblock the bootloader. otherwise the phone will get stuck on the Xiaomi logo.

Method 2: Recovery (without unlocking the bootloader)

This method is suitable if:

• ✅ You already have custom recovery installed (for example, TWRP).
• ✅ You are rolling back to a version that is no more than 1-2 updates older (e.g., with a new version). MIUI 12.5 on MIUI 12.0).
• ✅ You have a backup of NANDroid (if not, the method is risky!).

Instructions:

1. Download the firmware in Recovery ROM format (.zip file) for Redmi 9T.
2. Rename the file to update.zip and transfer it to the root of the phone’s internal memory.
3. Boot in Recovery: 1. Turn off the phone. 2. Press Volume Up + Power before the Mi Recovery logo appears.
4. From the recovery menu, select: Install update.zip to System (or similar) → Confirm installation → Wait for completion (5-7 minutes) → Reboot your phone

Critical: If the phone is stuck on the logo for more than 20 minutes after the firmware, then the MIUI version is incompatible with your current bootloader.

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If you have stock recovery (without TWRP), this method won’t work – Xiaomi’s stock recovery blocks the installation of old firmware.

Method 3: Use custom firmware (for power users)

If the official methods didn’t help or you want to install a modified firmware (like Pixel Experience or LineageOS), you’ll need to:

1. Unlocked boot loader (see Method 1).
2. Installed TWRP Recovery (instructions for Redmi 9T here)
3. Suitable custom firmware for the lime model.

Advantages of custom firmware:

• 🚀 High speed (no extra software from Xiaomi).
• 🆕 Up-to-date security updates (even for older models).
• 🔧 Flexible settings (such as kernel selection or processor overclocking control).

Risks:

• ⚠️ Loss of warranty (if the device is under warranty).
• ⚠️ Non-functioning modules (e.g, NFC camera-box).
• ⚠️ Blocking your Mi Account when you have incorrect firmware.

The following are the Redmi 9T firmware:

⚠️ Attention: Before installing custom firmware, be sure to make a backup through TWRP (Backup recovery will take 10-15 minutes, but save data if the firmware fails.

Frequent Mistakes and How to Avoid Them

Even experienced users sometimes make mistakes when downgrading, and here are the most common ways to solve them:

• 🔌 Phone is not defined in Mi Flash Tool: Check the cable (try another). Install drivers manually through Device Manager (download here). Disable driver signatures in Windows (instructions here).
• 📱 After the firmware, the phone is stuck on the logo: If you were stitching through Fastboot, repeat the process with the clean all and lock option (but this will block the bootloader!). MIUI (near-current).
• 🔒 Requires a password after the firmware: This means that the Mi Account is linked to the device. Enter the account from the phone before the firmware. If you forget the password, restore it to account.xiaomi.com.

If nothing works, go to the 4PDA or XDA-Developers forums – there are themes with solutions for Redmi 9T (look for lime code).

FAQ: Answers to Frequent Questions