I have an iPhone 4 that was/is Jailbroken. I believe it was running 4.1 but I honestly don't remember. I was tired of the crashes so I decided to just update to 4.2.1. I donwloaded the firmware without installing last night. Then today I tried installing it and it got stuck in recovery mode and gives me the USB/iTunes plug screen. I've tried opening the Terminal and amending the permissions to Apple's servers. I've tried RecBoot. And I've tried Exiting Recovery Mode through TinyUmbrella 4.21. I have no more ideas and Google gives me the same solutions. Or I'm probably tired and furustrated from trying. Please help. Thanks in advance. Update: I just tried Redsn0w 0.9.6b4 and it's still stuck.