Funny conclusion to my issue. When I started taking my PC apart, I decided to try booting one more time with the video card and wifi card removed. The system booted with the 3007 update successfully applied. I then configured the BIOS (I'd reset it via the battery & jumper), turned off the computer, put the video and wifi cards back in, booted, and it's working great. I'd checked the seating of all the cards before, so I'm very sure it wasn't that, but for some reason it needed to start once without the video card (I presume, though could be the wifi card) after updating. I can confirm there are some settings missing in 3007, but they don't affect me and unless I hear of specific bugs with it, I'm not risking re-flashing the old BIOS. I'm still very annoyed with ASUS for advertising a BIOS flashback capability that doesn't exist, and I think I've bought my last product from them, but at least I don't have to deal with an RMA anymore.