Ok I Upgraded to the official 2.2.1 upgrade from apple. I'm using Pwnage Tool. I'm running a Black Macbook with 10.5.6 but I did do the download to enable DFU mode. So I've already downloaded and made the custom firmware 2.2.1 and i'm trying to install it on my phone but after itunes extracts the file I get the error message, "The iPhone "iPhone" could not restore. An unknown error occurred (21)." Can someone please help me?