Xiaomi Redmi 9T (codenamed lime) remains a popular budget smartphone even years after its release. However, over time, the performance of the device can be reduced due to outdated software, bugs or the desire to install custom firmware. Phone firmware is a process that requires care, but with the right approach it is available even for beginners.
In this article, we will analyze all the current ways of firmware Redmi 9T: from official updates through MIUI Updater to install custom revers and alternative OS. Particular attention will be paid to unlocking the bootloader, without which most methods simply will not work. Also consider typical errors (for example, Fastboot mode or Anti-rollback check>) and how to fix them.
Before you start, make sure your device is at least 50% charged, which is critical to avoid the brick. You do all the manipulations at your own risk, but with accurate follow-up, the chances of success are 98% even for users without experience.
1. Firmware Preparation: What You Need to Know Before You Start
Redmi 9T is not a knee operation, it's your job to make sure your phone is still working. First and foremost, you need to identify the current MIUI and the model of the device.
- Go to Settings. → The phone.
- Remember or write down the MIUI Version (e.g. MIUI Global 14.0.5) and the Model Number (M2010J19SG for global version).
- Check the status of the bootloader: if the bootloader is blocked next to the Status, it will have to be unlocked.
Second, choose the type of firmware:
- 🔄 Official. MIUI — stable but limited by Xiaomi (advertising, limited settings).
- 🛠️ LineageOS, Pixel Experience – More freedom, but bugs are possible.
- 🔧 Stock firmware via Fastboot - clean installation, useful in crashes.
Important: If you are upgrading from Android 10 to Android 11/12, note that Redmi 9T has Anti-rollback protection. Downgrading the software version after the update can lead to a complete brick (the device will not even be included in the Fastboot).
⚠️ Attention: Fastboot firmware erases all data, including photos and contacts. backup via Settings → Additionally. → Backup and reset or use Mi Cloud (if it is unlocked in your area).
2 Unlock the bootloader on the Redmi 9T
Without an unlocked bootloader, you won’t be able to flash Redmi 9T through either the Fastboot or the custom reverie. Xiaomi officially lets you unlock the bootloader, but the process requires waiting and a Mi Account.
Steps to unlock:
- Link your Mi Account to your device: Go to Settings → Xiaomi Account. Enable Sync and Find the device.
- Activate USB debugging: In Settings → About Phone, click 7 times on the MIUI Version to enable Developer Mode. Return to Settings → Additional → For Developers and enable USB Debugging and OEM Unlock.
Use the Mi Unlock Tool
- Download the official utility from the Xiaomi website.
- Launch it on your PC, log in to the same Mi Account as on your phone.
- Connect Redmi 9T in Fastboot mode (turn off the phone, then press Power + Volume Down).
Where to download the official firmware?
- 🌍 Global version: official website MIUI (Choose Redmi. 9T → Global Stable).
- 🇨🇳 Chinese version: Chinese portal (requires a Mi Account).
- 🔍 Version Archive: Sites like Xiaomi Firmware Updater (check hashes of files!).
| Type of firmware | Advantages | Deficiencies | Suitable for |
|---|---|---|---|
| Stable (stable) | Maximum reliability, minimum bugs | Updates are less frequent, there are no new features | Users who care about stability |
| Developer (developers) | New features, weekly updates | Possible bugs, less optimization | Enthusiasts and testers |
| Fastboot (full) | Clean installation, corrects system errors | Wipes data, requires PCs | Addressing serious disruptions |
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The update via MIUI Updater does not require unlocking the bootloader and saves user data, but it only works for official firmware and does not allow you to downgrade the MIUI version due to anti-rollback protection.
4. Firmware via Fastboot (complete reinstallation)
Fastboot Method Suitable for Redmi Resuscitation 9T after a crash or a stock firmware installation. It requires a PC, USB-cable and unlocked loader.
Tools required:
- 🖥️ PC Windows/Linux and installed drivers ADB/Fastboot.
- 📁 Firmware in.tgz or.zip format (download from the official website).
- 🔌 Cable USB (Better original to avoid communication breaks).
- 🛠️ The Mi Flash Tool (download here).