OMG you guys are my hero.
"For any of the poor souls that were greeted by the update failed message, flipped out, and nearly took a hammer to their head unit:"
This was me!!!!
So I used 3 different sd cards, on a Mac all following the rules. Then I abandoned the Mac reformatted the cheapest basic sd card I had on a pc, re downloaded and extracted, and it worked
I don't have a $800 brick, thanks guys!
fwiw to the community, my message was same as the OP but instead of saying USB it said SD as this was the medium I first tried the update with. It appears if your unit h