Since UFI software version 1.2.0.371, UFI supporting Flashing and Repairing Imei Mediatek Devices.
Case : Deadboot Oppo Find 5 Mini (R827)
Replace eMMC using Samsung KMKJS000VM-B309 (4GB/1) BGA 162
Follow procedure in video
https://www.youtube.com/watch?v=MoQhJCcgIB4