How to Install MIUI 9 ROM Using Fastboot Mode
This method relies on Fastboot utility and requires you to have a computer. Make sure, your device’s bootloader has been unlocked as well.
Step 1 – Download “Fastboot ROM” for your Xiaomi device from the list given above. Once downloaded, extract the file anywhere in your computer. You may again have to open the extracted file using WinRAR or WinZip and extract it again (manually / by force) till you see several files similar to the ones shown below.
Step 2 – Download Xiaomi USB Drivers and install them on your computer. You need these to make sure your phone works well with the PC.
Step 3 – Download Mi Flash Tool on your computer.
Step 4 – Turn OFF your Xiaomi device before proceeding.
Step 5 – Now boot the Xiaomi device into Fastboot Mode. How? You can enter Fastboot Mode on your phone by holding Volume Down + Power buttons while the phone is OFF. If you see a similar screen as shown below, this means you are in the Fastboot Mode.
Step 6 – Connect the phone now with your computer. Your PC will recognize the device and install the necessary drivers to set it up for use.
Step 7 – Open Mi Flash Tool.
Step 8 – Click on the select button and choose the directory where you extracted the Fastboot ROM files in Step 1. Then click the refresh button. Mi Flash Tool will recognize the files and display device info on the screen. You should see something like as shown in the screenshot below.
Step 9 – IMPORTANT – From the bottom of Mi Flash Tool, select the middle option that says “save user data” if you do not want to wipe all your data.
Step 10 – Now click the flash button to start the installation.
Step 11 – Your phone will reboot once the installation completes.
This is it! MIUI9 should now be installed on your phone.
You can go to Settings > About phone to see what version are you running on you phone.