To be perfectly honest, I may have the wrong idea about what the "DFU screen" is. What came up was the screen that shows the USB and iTunes logos.
To advance my cause a bit, since I don't know anything about blackrain, if/when I get a different 3gs, I'd like to just stick with pwnage tool since I've used it multiple times. What I'm curious about is if that possibly didn't work because I tried blackrain first.
Also, another thing that's gone through my mind is that I may have had a problem because I tried to jb before setting up the phone via itunes at all. I want to restore the 3gs to my 3g settings, but I know I don't want to update to 3.1.3 in the process. During an initial restore, will I be able to successfully manually load an ipsw built by pwnage tool? That's what I couldn't get to happen without an error in my previous attempt, despite multiple tries. Is that possibly because I tried blackrain first?