so, i’ve tried to jailbreak my old iPhone 3G with pwnage tool 3.1 & was getting error 1600. after 2 days, i found that deleting content of ~/Library/iTunes/Device Support/ … allowed my to finally jailbreak, but …. i did have my sim card in the phone while firmware restore was finishing & it didn’t activate the phone . so when i tried to jailbreak again … error 1600 (this time deleting “… device support” didn’t help & yes i tried both dfu methods).
is quite simple (works on new aluminum macbook pro) – use redsn0w.com! (also by dev team) to not only jailbreak, but also unlock so you can use any cell provider’s sim card (of course works with att as well). i’ve used it with firmware 3.1.2 because 3.1.3 has some issues & didn’t want to spend day 4 on figuring it out.
ps: mywi cydia app WORKS, so that iPad tethers of your iPhone! … it is a 9 day trial & then $9.99