LM8600 US Version "network is disabled" issue

Please excuse my English usage.

I have a 55LM8600 US version stuck with the "engineer mode" misnumbered version of 09.99.00.

I have everything setup to downgrade to 06.04.03

However, every time the download process gets to 100% it stops and I get the popup error of "the update has been suspended because the network has become disabled".

I've tried different image sizes, dates, and "REQ ID"s in the HE_DTV_GP4H_AFAAATAA file, and even tried different firmware versions (06.01.03 and 05.01.36) with no luck.

I'm using the "USB" versions as offered from LG.com

I've tested the TV at the Russian site and it is properly detected and offered 00.00.00.

Obviously, I'm trying to save a few dollars and simply want to address this myself now and in the future.

Is there some secret to fixing this error (I've noticed many other people getting it)?

Thanks in advance.