Having same problem. Won't boot up after Radio 3.35.04 flashed. Get some really weird gunk on the first boot screen with the device info.
Done the hard reset, taken battery out for over an hour. Basically tried everything I could find on these forums. Its wierd because I've already flashed several of these to the new Radio, but this was the first time I've used the Radio updater from ppcgeeks ftp
I used this one
ftp://up.ppcgeeks.com/Titan/Radios/t...io_3.35.04.exe
Every other time I flashed the Verizon xv6800 I used the Sprint official rom, and just didn't let it boot after the flash. It worked perfectly then.