這是官方說明: How to Flash Fastboot Firmware with Miflash Tool This is a program bringing system alterations. So before moving to the process make a backup and try saving all the existing data. And then, proceed with high attention.
Step 1: Download the correct Fastboot ROM on the Windows PC by double-checking the compatibility. Then extract and get the workable extensions on the PC Step 2: Download Xiaomi Flash Tool Free on the PC and unzip Step 3: Move to the installation through the exe file from the folder Step 4: Continue to “Browse” by entering the tool interface Step 5: Then attach the ROM file Step 6: Switch Xiaomi device into the Fastboot mode. So turn off the device and simply take a long press and hold the keys of Volume Down and Power keys Step 7: Then connect the device to the PC with a proper USB cable which is in the Fastboot mode Step 8: Now you can enter the tool interface and check whether the device is connected Step 9: Then select the most suitable flashing option from all three “Flash all”, “Flash all except storage” and “Flash all except data and storage” Step 10: Hit flash from the top of the window and wait for several minutes Step 11: Once the process is done you can reboot and finalize the process successfully.