Don't expect a iOS 4.3.4 untether anytime soon.
In a way it is nice to see that Apple instead of merely fixing vulns add more mitigation checks. But for jailbreakers this suxx.
As we have already mentioned several times, do not update to iOS 4.3.4. Instead, use JailbreakMe to jailbreak your device on iOS 4.3.3. You can find instructions on how to do this here.