Can't Flash Via Fastboot In Miflash As Per Unlock Guide

Feb 27, 2017
Mi4C currently running 7.2.9 weekly. I'm trying to unlock the bootloader after upgrading to Android 7.0 from 5.1. But all attempts at flashing a downgraded version (libra_images_6.1.7_20151221.0000.11_5.1_cn and, which are both recommended by wolkenjaeger's guide) fails after 14 seconds. I'm following the linked guide to the letter. Also tried the latest MiFlash. 'fastboot devices' show the Mi4C before 'fastboot oem edl' and flashing the images directory of each version via the MiFlash tool.

MiFlash stops with a ping target error message in the UI after 14 seconds of flashing both downgraded versions mentioned above. Flashing as intended before the error stops the process. I have attached MiFlash log files for a flashing attempt for each.