I did it as following:
1- I downloaded Stable ROM for my Mi 11 Ultra in my PC from this link (https://drive.google.com/file/d/1jsKyUOxHRFlM6OVMv3P4X6mlHI0kyEyy/view?usp=sharing) because speed of mirrors Sourgeforce was low
2- I put this file in my device by USB
3- I booted in TWRP my phone (ON...