Can I downgrade from 4.2.6 to 4.2.1???

[Wisiphone79]

I have my Iphone "jailbroken" with 4.2.6 software and im learning a lot of Themes and some Apps only work with the 4.2.1 software. Is there a link for step my step instructions on how to do this or just waite till Cydia updates there software? Thanks

 

[iGaz]

Verzion iPhones can't go to 4.2.1 as they were never on it...