I flashed it via fastboot, like a normal stock rom (but your bootloader needs to be unlocked).
About the link, I took it from this forum. I'll link the forum post here:
sooo people who had their oem locked are ****ed? ... great and let me guess we can't even ask a refund? ... I mean there's no way to install anything on the phone at this state.... even if they roll out the fixed version.
OEM unlock not working since phone is bricked.
MiFlash shows error while installing since oem is locked.
ADB fastboot is the same.
fastboot getvar all