Fastboot flash failed

I’m trying to flash my Hi10 Pro PQ 64G 42 1611 with Android. I downloaded the file from “the main download topic” [Hi10 Pro] [Official Version] Chuwi Hi10 Pro Windows, Android, Bios, Driver, tutorial Download

When I try to flash with Intel Platform Flash Tool Lite I get the following error:
12/15/19 22:03:35.821 WARNING: [Port 0/1/4] Command "C:\Program Files (x86)\Intel\Platform Flash Tool Lite\fastboot.exe" "-s" "EMMC1D476952" "flash" "fw_stage2_osdnx" "C:\Users\Pauly\Downloads\Chuwi\Android Hi10 pro (P) 20161103-2\安卓软件\firmware.bin" failed

The tablet is in DNX FASTBOOT MODE. With an USB <> USB-C cable (although I’m not sure if it’s the original one).

After some more investigation it seems that all fastboot commands fail:
PS C:\Program Files (x86)\Intel\Platform Flash Tool Lite> fastboot getvar all getvar:all FAILED (remote: unknown command) finished. total time: -0.000s

Only listing the devices does work however:
PS C:\Program Files (x86)\Intel\Platform Flash Tool Lite> fastboot devices EMMC1D476952 fastboot

What could be the problem?