I ran the update today and noticed that I was getting no video output. I plugged it direct into my TV and it worked. Since I have no intention of not using my audio receiver I downloaded the recovery image for the previous SW and flashed that via Fastboot.
Others on the Shield forums are also having this issue FYI.
Also if you revert back to the previous working release and try to set up the shield it will automatically download and install the 2.0 update.
I was so pumped for this update only to be driven mad!