Cannot install custom firmware on V3.0 Device

[dmavromatis]

I've followed both @ludwig-v, but he keeps saying it user error -- I have confirmed over and over using a v2.0 device it works, but on this particular v3.0 it will not take a custom firmware:

These instructions do not work!!
#110
-and -
#111

It's impossible to install CFW on this device. I have successfully updated using v2.0 devices (3 of them) but the v3.0 it will not work.

I currently have the ver: 2020.11.10.2139 (ROLLBACK) on the v3.0 -- as shown on the internal webpage @ 192.168.50.2, it's still a red interface. This was from the factory which was 2021.07.05 -- but the "downgrade" was fairly quick -- not like a real update -- but I guess it's correct since the internal webpage shows correct version.

When I download CFW ver 2021.08.24_BASED and place on a USB named: U2W_Update.img it does nothing.
If I name it: U2W_AUTOKIT_Update.img it says "Updating do not power off..." then goes to "Update failed"

This also happens if plugged directly into USB power and doing it without head unit.

Any ideas? Has anyone actually installed CFW on a v3.0 dongle?