Saurik has just released an update to Cydia that brings us one step closer to a stable jailbreak. Cydia 1.1.14 no longer causes your device to lock up while booting on iOS 8 when you use a passcode.
The iPhone Dev-Team has confirmed that RedSn0w 0.9.6b2 can jailbreak iOS 4.2 GM Seed; however, they warn it should only be attempted by advanced users.