initial situation:
bricked Mi 4c without Unlock
process:
download Fastboot Rom
"Xiaomi Mi 4c Latest China Stable Version Fastboot File Download"
extract Fastboot ROM to directory (e.g. "libra_images_V9.5.1.0.NXKCNFA_20180306.0000.00_7.0_cn")
download twrp-3.1.1-1-libra.img
copy...