Can't restore Jailbroken iPhone 3GS

[laurenbroccoli]

Okay, so my old iPhone just got replaced by Apple because it was still under warranty. My old iPhone was jailbroken and was backed up on my computer. So when I got a new one, I restored it with my old iPhone's settings and things. I jailbroke it and everything. Then I noticed that service was EXTREMELY spotty. At first I thought this was because it was new and had to activate, but I learned it wasn't just that. I tried to restore it back to factory so I could take it back to Apple to get it replaced but it gave me the iphone could not be restored unknown 3194 error. Before I tried to restore it I believe it was running 4.0.1, when I tried to restore it, it said something about it updating. I didn't look to see if it was successful but I'm pretty sure it was.

I tried editing the host file and putting it in recovery mode.
Also, when I jailbroke it I clicked the "make my life easier" button in cydia.
Please someone tell me that I can restore it? I just want the jailbreak gone so I can take it back in.
I just downloaded TinyUmbrella... but I'm not quite sure what to do with it.

[iYeow]

After you download TU, plug it in and click save shsh. You will see what shsh you have. If you only see 4.2.1 and nothing else, then you can only restore to 4.2.1 fw