@tom, @jjd

The brown screen you see is from the TV module. It looks like the update to your NAV unit did not work so the TV module has taken over as the bootup OS. Hence the brown screen. I'd make sure that when you burn a new copy of the update, make sure you use the slowest burn setting within Alcohol120% and also the media is of some reasonable quality (ie maxwell, tdk, etc...)

Ensure that you downgrade with the steps mentioned above and then follow same steps to upgrade.