I've mistakenly jailbroke my iPad 4.2.1 using PwnageTool 4.3.3. Now I want to unjailbreak so I can jailbreak again using GreenPois0n. When I google about unjailbreak, it says just restore the iPad. The problem is I can't restore or update as error 3194 keeps appear everytime I try to do so. Please help me.