Hey folks we told you before that you must wait for a proper confirmation before running the Untethered Jailbreak on the previously Jailbroken iDevices. This means that those people who were on iOS4.2.1 and were having a Tethered Jailbreak on their iDevices can now run Untethered Jailbreak on it. To do the Untethered Jailbreak you can follow our complete guide here.
This was confirmed by @MuscleNerd that:
Yes,tethered 4.2.1 redsn0w JBers can just run #greenpois0n over it for untether (restore only if you have problems)
The best thing about the relationship between GP and redsn0w is:
The order doesn’t matter: run GP after redsn0w, or run redsn0w after GP)
So the order really doesn’t matter whether you run GP first or Redsn0w first or vice versa. So this means you wont need to restore back your Device in order to Run GP. You can use greenpois0n on the already Jailbroken iDevice via redsn0w.
But for those who used iOS4.2b3 SHSH and iOS4.2b3 firmware and the jailbreak Monte procedure to do a Untethered Jailbreak and want to use Greenpois0n so they will need to do a complete restore.