I own an iphone3g 8gig running ios 3.1.3(got it like that), ive never upgraded an iphone before and its unlocked,jailbroken with lots of appsync from cydia apps,how do i upgrade to ios 4.2.1 without losing the apps or crapping up the iphone,... i would love a detailed guide on upgrading this type of iphone(unlocked and jailbroken)