Xiaomi Mi 9T firmware: official and custom methods with unlocking the bootloader

Xiaomi Mi 9T (The codename Davinci remains a popular smartphone even years after its release, thanks to its powerful hardware (Snapdragon 730, AMOLED-The screen is also supported by the development community, but over time, the official updates have been made. MIUI They stop coming out, and users are faced with bugs, brakes or the desire to install custom firmware like LineageOS or Pixel Experience. In this guide, we will analyze all the current methods of firmware - from standard updates through the Internet. MIUI Updater to manual installation via Fastboot and TWRP.

It’s important to understand that firmware is not only a way to upgrade the system, but also the risk of turning the phone into a “brick” if you break the sequence of actions. Especially this applies to unlocking the bootloader on the Mi 9T with MIUI 14+, where Xiaomi has tightened the rules (now requires an account binding to the device for 720 hours), We will describe each step in detail, including bypassing possible errors such as Anti-Rollback or Invalid Image, and give recommendations for choosing firmware for specific tasks – whether it is performance, camera or battery life.

1. Firmware Preparation: What to Do Before Starting

Before you start firmware, make sure that critical conditions are met, which will save time and prevent most errors.

• 🔋 Battery charge at least 60%, firmware can take up to 30 minutes, and discharging during the process will cause a failure.
• 💻 Computer on Windows 10/11 (for Fastboot or Linux/macOS (for ADB). On Windows, be sure to disable driver signature!
• 📶 Network connection. Only download firmware through stable Wi-Fi, mobile Internet can interrupt the download.
• 🔐 Backup. Use Mi Mover or TWRP Backup for data storage (contacts, SMS, applications).

The software part is just as important. Here's what you need to check:

• 📱 Version. MIUI. Find out her in Settings → The phone. → Version. MIUI. For Mi. 9T Applicable firmware based on Android 10–13.
• 🔓 bootloader status: If it is locked (by default), unlocking will require up to 30 days of waiting.
• 🛠️ Download: Mi Unlock Tool (to unlock) Platform Tools (ADB/Fastboot) TWRP for Mi 9T (if you need custom firmware)

⚠️ Attention: If your Mi is yours 9T purchased in China (suffixed version) CN In the model, you will need a Chinese phone number to connect the account to unlock the bootloader (Global/EEA) It's not required.

2 Unlock the bootloader on Xiaomi Mi 9T

Without an unlocked bootloader, you will only be able to upgrade via MIUI Updater - installing custom firmware or even official through Fastboot will not be possible. Xiaomi has made the process more complicated in the latest versions of MIUI, so follow the instructions carefully.

Step 1: Linking your Mi Account to your device

1. Go to Settings → Mi Account → Security.
2. Find the bootloader Unblock Status and click Add Account and Device.
3. Confirm the binding through SMS/email. Please note: c MIUI 14+ The waiting time for unlocking is increased to 720 hours (30 days).

Step 2: Use the Mi Unlock Tool

1. Download and install the Mi Unlock Tool.
2. Run the program on behalf of the administrator and log in under the same Mi Account that is linked to the phone.
3. Put the phone in Fastboot mode: turn it off, then press Volume down + Power.
4. Connect your phone to your PC via USB and press Unlock in the program. wait until it is completed (it can take up to 10 minutes).

⚠️ Note: If the Mi Unlock Tool gives you a Couldn't unlock error, check if the phone is connected to the original. USB-port (not hub) are Qualcomm drivers installed HS-USB QDLoader 9008 (downloadable XDA). Is it not being used? VPN/Xiaomi blocks unlocking from some regions).

Linked to the Mi Account to the device|Installed with Mi Unlock Tool|Phone in Fastboot mode|Antiviruses and firewall disabled|USB-Original cable (not cheap replacement)-->

3.Firmware methods Xiaomi Mi 9T

The choice of firmware method depends on your goals:

Let’s look at each method in more detail.

3.1. firmware via MIUI Updater (the safest way)

This method is suitable for installing official updates without the risk of data loss, but only works if:

• The phone's not rooted.
• The sleeve is not a sleeve (not a sleeve).
• There are no anti-rollback errors.

Instructions:

1. Go to Settings → About the phone → System update.
2. Click on the three dots in the top right corner and select Select the Update File.
3. Specify the path to the downloaded firmware file (.zip format).
4. Wait for the check and click Reboot and Update.

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If the update is stuck in the verification phase, try renaming the firmware file to update.zip and putting it at the root of the internal memory.

3.2. firmware via Fastboot (MiFlash Tool)

This method is used to completely flash the phone, including recovering from soft-brick (when the phone does not load but reacts to the Fastboot).

Step-by-step:

1. Download the official firmware for your model (for example, davinci_eea_global European version).
2. Unclose the file and place the firmware folder in C:\MiFlash.
3. Install MiFlash Pro.
4. Transfer the phone to Fastboot (Loudness down + Power).
5. In MiFlash, select the firmware folder, press Refresh (should appear). COM-port) and click Flash.

⚠️ If MiFlash is making an error flash_all_lock.bin Failed means the bootloader is not unlocked. flash_all_lock.bat file flash_all_except_storage.bat — This will save your data, but does not guarantee stable operation.

Firmware via TWRP (for custom firmware)

To install LineageOS, Pixel Experience or other custom firmware will require TWRP Recovery. It's important to use the current version for Mi. 9T (for example, twrp-3.7.0_9-0-davinci).

Instructions:

1. Download TWRP.img and firmware (e.g. lineage-20.0-20230612-nightly-davinci-signed.zip).
2. Transfer your phone to Fastboot and execute the command: fastboot flash recovery twrp-3.7.0_9-0-davinci.img fastboot boot twrp-3.7.0_9-0-davinci.img
3. In TWRP, make Wipe → Format Data (required!), then install the firmware through Install.
4. After installing the firmware, re-sweeten TWRP (otherwise it will be replaced by stock Recovery).

4. Solving common firmware errors

Even if you follow the instructions accurately, you can get errors, and let's look at the most common ones and how to fix them.

Additional advice:

• 🔄 If the phone is stuck on the Mi logo after firmware, try going to Recovery (Loudness up). + Food) and make a Wipe Cache.
• 🔌 If your PC doesn’t see your phone in Fastboot, try another one. USB-Port or cable (preferably original from Xiaomi).
• 📡 If there is no network after firmware, check the settings APN Or re-flash the modem module separately.

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If after firmware through Fastboot the phone does not turn on, but reacts to the connection to the PC (vibrates, the indicator burns), try flashing only the boot section with the command fastboot flash boot.img. Often this solves the problem of the “black screen”.

5. firmware choice: official MIUI vs custom

Decide which firmware to install, will help to compare their features:

Selection recommendations:

• 📱 For everyday use, official MIUI (Stable, better camera).
• 🚀 For performance – Pixel Experience (pure Android with updates).
• 🔧 LineageOS (flexible configuration, but may be less stable).
• 🎮 For gaming - custom cores of the Perseus type (overclocking) CPU/GPU).

Download the firmware only from verified sources:

• 🌐 Officially: MIUI Downloads.
• 🔧 Castomic: XDA-Developers (Mi section) 9T).
• 📦 Firmware Updater: Xiaomi Firmware Updater.

6. Post-firmware optimization

Successful firmware is only half the battle, so to keep your phone running fast and stable, take a few extra steps:

• 🧹 Cache cleanup. After the first download, go to Recovery and select Wipe Cache.
• 🔄 Calibrate the battery. Discharge the phone to 0%, then charge to 100% without interruption (repeat 2-3 times).
• 📸 Set up the camera. For custom firmware, install GCam with config for Mi 9T.
• 🛡️ Security. If you've stitched custom firmware, install Magisk to manage root access.

Useful tweaks for MIUI:

• Turn off Miui Optimization in the developer settings (Settings → About Phone → MIUI version → 7 times tap).
• Install ANX Camera for improved video shooting.
• Use Greenify to limit background processes.

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If the speaker is missing after firmware, check the Device Manager settings in Windows (sometimes the audio drivers get lost). On your phone, go to Settings → Sound → Sound Quality and select High.

7.Firmware rollback and downgrade

Sometimes you need to return the old version of MIUI — for example, if the new firmware is unstable or eats up the battery. However, Xiaomi has implemented an Anti-Rollback mechanism that blocks the rollback of older versions.

How to check for Anti-Rollback support:

1. Check out the current version in Settings → About Phone → MIUI version.
2. Compare this with the compatibility table at Xiaomi.eu.

Instructions for Downgrad (if permitted):

1. Download the required firmware version with the same Anti-Rollback number.
2. Swipe it through Fastboot (MiFlash) with the Clean All tick.
3. If the phone is not loading, run the vendor and system separately: fastboot flash system.img fastboot flash vendor.img

⚠️ Warning: Downgrade to the lower version of Anti-Rollback will result in a hard-brick (the phone won't even be included in the Fastboot) and can only be restored via a hard-brick. EDL-Mode (requires an authorized Xiaomi account).

FAQ: Frequent questions about Xiaomi Mi firmware 9T