How to jailbreak iPod Touch 4g on 4.2.1?

So i tried jailbreaking my ipod with limera1n and it worked but the icon never appeared and iit didnt work. Then i tried greenpois0n which also didnt work. So i thought it ight have to do with me having 4.2.1. o i tried downgrading my OS to 4.1. I used tiny umbrella and went to restore it but it just said Itunes error (1600). So then i tried using redsn0w but just tried to boot it in pwned DFU and using tinyumbrella gain it got further then be for and i thought it was gonna wor it restored it and everything and it said it would restore my ipod but then it just stopped and on my ipod in itunes it jut said that i had to restore it again. Then i tried restoring it again and gave me the itunes error (1600) so whats up and how do i fix this?