DFU problem, not a noob here

ok first off, ive been on this forum since the first iphone was JBed, so i know what im doing.

i jb my 3G from 3.1.2 to 4.0 with pwnage tool that worked liked a charm ::thumbs up::

ok now i have a friends 3Gs, he told me its on 3.1.3, and it was Jb (not with spirit).

my issue is that it only comes up with the itunes logo, when i go to go into DFU using pwnage, when i turn it off, and im gettin ready to hold the power and home it fails because the itunes logo came up right away.

so i close pwnage tool, and do it myself, i checked on my pc if it was in it by checking the bootrom, which is also good(on the old one)

but when i go to restore using my custom .ispw, i hit a 1600 error?


ok but tomorrow, im going to my friends (who works for AT&T) house, and using his sim card to activate so i can get to the normal screen.

other than that any suggestions from anyone?!