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 Firmware: Obtain the official firmware for your Xiaomi Redmi Note 9S. Ensure it’s compatible with your device model.

2. Install Drivers: Install MediaTek USB VCOM drivers on your computer so that the SP Flash Tool can communicate with your device.

3. Charge Your Phone: Make sure your device has sufficient battery to prevent any interruption during the flashing process. (at least 50%).

4. Backup: Flashing firmware will erase your device data. Back up your important files before proceeding.

Steps to Flash Firmware using SP Flash Tool:

1. Download and Extract SP Flash Tool:

   • Download the latest version of SP Flash Tool from a trusted source.
   • Extract the downloaded ZIP file to a location on your computer.

2. Install VCOM Drivers:

   • Navigate to the SP Flash Tool folder and find the “Driver” sub-folder.
   • Run the “Install.bat” file to install the MediaTek USB VCOM drivers.

3. Run SP Flash Tool:

   • Locate and run the “flash_tool.exe” file within the SP Flash Tool folder.

4. Load Scatter File:

   • In SP Flash Tool, click on the “Scatter-loading” button.
   • Navigate to the firmware folder and select the scatter file (usually named “MTxxxx_android_scatter.txt”).

5. Configure Flash Options:

   • Once the scatter file is loaded, you’ll see a list of partitions. By default, all partitions are selected.
   • You can select/deselect the partitions you want to flash. However, it’s recommended to keep them all selected for a complete firmware flash.
   • Make sure the “Download Only” option is selected.

6. Turn off Phone, Connect, and Start Flashing:

   • Power off your Xiaomi Redmi Note 9S.
   • Connect your phone to the computer using a USB cable while holding the Volume Down button.
   • SP Flash Tool will detect your device and start the flashing process. A progress bar will appear.

7. Flashing Complete:

   • Once the flashing process is complete, you’ll see a green checkmark indicating success.
   • You can now disconnect your device and power it on. The first boot may take a bit 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.