Note: Flashing firmware can be risky and might lead to data loss or even bricking your device if not done correctly. Make sure to follow the steps carefully and back up your important data before proceeding.

Prerequisites:

1. Download and install the Xiaomi USB drivers on your computer.
2. Download the appropriate firmware for your Xiaomi Redmi 9T. Make sure you’re downloading from a trusted source.
3. Download and install the SP Flash Tool on your computer.
4. Make sure your device has sufficient battery to prevent any interruption during the flashing process. (at least 50%).

Steps:

1. Install SP Flash Tool:

   • Install SP Flash Tool on your computer if you haven’t already.

2. Extract Firmware:

   • Extract the firmware files you downloaded earlier.

3. Open SP Flash Tool:

   • Launch the SP Flash Tool on your computer.

4. Load Scatter File:

   • In the SP Flash Tool, click on the “Scatter-loading” button.
   • Navigate to the extracted firmware folder and select the scatter file (usually named “MT6xxx_Android_scatter.txt”). This file will contain information about different partitions of your device.

5. Choose Flashing Options:

   • Once the scatter file is loaded, you’ll see a list of partitions to be flashed. Make sure everything is selected by default.
   • Choose the appropriate flashing mode based on your needs. “Download Only” is generally used for a full firmware update.

6. Connect Your Device:

   • Power off your Xiaomi Redmi 9T.
   • Connect the device to your computer using a USB cable while holding the appropriate button combination (usually Volume Up or Volume Down). This will initiate the flashing process.

7. Start Flashing:

   • After connecting the device, click the “Download” button in the SP Flash Tool.
   • The tool will start flashing the firmware to your device. You’ll see a progress bar indicating the process.

8. Completion:

   • Once the flashing process is complete, you’ll see a “Download OK” message.
   • You can now disconnect your device and power it on. The first boot might take a little longer than usual.

Remember that these instructions are based on general steps for flashing MTK-based devices. The exact steps might vary slightly based on the specific firmware and version of SP Flash Tool you’re using. So we can’t take responsibility for these instructions. Always refer to the official documentation and resources for your device and tools.