http://en.miui.com/forum.php?mod=viewthread&tid=228054&extra=page=1&page=1&mobile=2
1.Flash China Dev
2.Unlock Bootloader
3.china dev have root , you can flash twrp via Flashify
Do you read this
http://www.androidbrick.com/unbrick-all-qualcomm-snapdragons-from-qualcomm-hs-usb-qdloader-9008-if-you-have-the-right-kind-of-rom-qhsusb_dload/