EFI Firmware 1.7 won't update on late 2012 Mac Mini

I bought a 500 GB i5 Mac Mini last Dec. I set it up and updated it to 10.8.2 and updated the EFI Firmware to 1.7 to cover the HDMI flicker issues. But I decided that I wanted to start over from scratch so I re partitioned and did a clean install of Mountain Lion from the recovery disk. All was well until the signal my HDTV was receiving from the Mini started flickering on and off. I hooked it up to a VGA monitor (which worked fine BTW) and tried to install the EFI update but now get a message saying "the software is not supported on this system".

1. Do I need to update my EFI Firmware after a clean system reinstall?

2. If the answer to number 1 is no, then could there be a hardware problem with the graphics card?