Flashing MIUI ROM in Fastboot Mode :
Download necessary ROM and ROM Flashing tool, and make sure that your phone has enough power. This guide will help you to upgrade your Global stable ROM to the Global developer ROM. All user data will be cleared in the process, so please back up your personal data on your PC/Laptop before starting this process.
1. Download a FastBoot ROM and extract it on desktop
(Please check if the file suffix is '.tgz'. Please rename it to '.tgz' if the suffix is '.gz or .tar')
2. Download flashing tool and install it.
3. Once installation complete, double click on MiFlash icon
4. Click on browse
5. Select ROM folder from Desktop
6. Click on Advanced.
7. Click on Fastboot Script Browse button then go to ROM folder from desktop and select flash_all.bat, This will wipe all data from Internal SDCard so make sure you are taking all personal data backup on PC/Laptop.
8. Turn off the phone, press the Volume down key and the Power button at the same time to enter Fastboot mode, then connect the phone to a computer.
9. Press Refresh button to see you device in flashing tool.
After pressing refresh button you will see connected device.
10. Click on Flash and it will start process
11. Once flashing process completes, device will automatically reboot. Reboot might take upto 5min.