Press and hold simultaneously until you feel a vibration.
Use this if your phone is stuck in a bootloop. Note: This will .
Sometimes the system just needs a forced restart to clear a temporary glitch.
Release the when the Mi logo appears, but keep holding Volume Up until the "Main Menu" (Recovery) appears.
Use the Volume buttons to highlight and the Power button to select it. Select Wipe All Data and confirm. Once finished, select Reboot -> Reboot to System . Phase 2: Flashing Stock Firmware (Fastboot Brick)
If Recovery Mode fails or you are stuck on the screen, you must flash the official stock ROM using a PC. Prerequisites Downloads - Xiaomi Community

