I've got an iPhone 2G which won't upgrade. When I try on my MacBook, and try to restore to an ORIGINAL ipsw, it won't get past this in iTunes:

(It says restoring iPhone-software)

and this on iPhone:

When I try it on my Windows machine, I'm getting error 1600 or error 2 (guess that depended on DFU mode or not)

When I try it on my MacBook OR Windows machine with Redsn0w (with 3.1.2 since it doesn't recognize the 3.1.3 IPSW) everything works fine, but when Redsn0w reaches "activating" (on the iPhone, so it's all done on the computer) I'm seeing the spinning wheel, which stays there.

I'm really out of options, who's got an idea for me?