Trying to Jailbreak iPhone 4.2.1 and failing

[jayxmoneyx101]

So as of last night I had a jailbroken iphone 4 on 4.1 and everything was working fine until my roommate decided to change my passcode and wouldn't tell me. I decided I would restore my phone like an idiot because I got impatient. I then thought it would be a good time to try and upgrade to 4.2.1 and just jailbreak that.

However, I was having serious problems doing that on my computer getting several different error codes so I did it though iTunes on my roommates (he felt bad) and it worked. I've tried jailbreaking it with greenpoison and redsn0w and both of them fail to install cydia.

I did some searching and it said that there were some problems and going into the files and deleting something would make cydia show up but the program I used, iPhoneBrowser, is saying that my phone isn't even jailbroken.

Is it because I updated it "legit" through iTunes and am now screwed forever? I've searched the internet for hours with no answers that seem to solve my problem.

Thanks.

EDIT: Just tried greenpoison again and I get: "Jailbreak Failed"

[iYeow]

Restore to stock 4.2.1 again, put your official sim card to activate and jailbreak with GreenPoison again. There should be a loader, do a reboot of your iphone first.