Hi there, sorry for a stupid question, i am a total noob, but basically i bought an iphone 4 a while ago, it had iOS 4.0 on it, and when 4.1 came out i updated normally through iTunes and then jailbroke it with Greenpoison. My girlfriend just bought an iPhone 4 too with iOS version 4.0, so since 4.2.1 is out i downloaded 4.1 manually and tried to install it through update (press shift) on iTunes and half way through i get an error message and it wants to restore to factory settings and then update to 4.2.1. What am i doing wrong, i have read around and i think its because iTunes doesn't sign for it anymore because of 4.2.1 being out and maybe something to do with SHSH blobs maybe, don't really get it....help anyone thanks in advance for any assistance