Need help jailbreaking iPhone 3G 4.2.1

[CalebWood1]

My iPhone was jailbroken once before and it worked fine on 4.2.1. I started messing around with the files too much and ended up having to restore it. Now, when I try to jailbreak it, it won't work. Redsn0w won't recognize the ipsw file (and it's ipsw, not zip) and and won't go into DFU mode when I try using GreenPois0n. I don't know if I have to downgrade or restore it again or what, but any help would be greatly appreciated.

[kraziebone]

You shouldn't need to downgrade your phone. I had a similar problem with redsn0w on 4.2.1, for some reason it wouldn't recognize my ipsw, try redownloading the firmware from another place and pointing redsn0w to that file. Another thing you might want to try is running redsn0w in windows xp compatibility mode

[bondkt]

if i recall correctly, dev team never made a redsn0w for ios 4.2.1 that was untethered?

use sn0wbreeze, pwnagetool\greenp0sion, pwnagetool\sn0wbreeze being easy and extremely customizable...

DFU is the biggest pain...use ireb to help you put phone in DFU, then restore to custom or gp to to jb it