4.2.1 Downgrade to 4.1 Problems, Problems, Problems

[CMull123]

I've been trying to downgrade my friends iPhone4 4.2.1 to 4.1 so we can jailbreak it for quite a while now and we're having a ton of problems.

At first we would get stuck verifying it with Apple, then remembered tinyumbrella and we got right past that part. Here's what I think could be the problem, this phone has never had 4.1 on it, it began it's life at 4.2.1. Although I would imagine that this hangup would be during the verifying phase of the restore. When we look up the SHSH's saved for that phone we get 4.2.1 8C148 and 4.3b2 8F5153d. The part that usually hangs up is while it says "Preparing phone for restore" and then we get one of the numerous 16xx errors.

Is he stuck until there's a full 4.2.1 jailbreak or are we just doing something wrong?

Also, this isn't my first time around, I've had 3 iphones of mine that I've jailbroken with no problem and I've done a few other friends' too.

[i.Annie]

If the phone came with 4.2.1, it has no SHSHs for 4.1, therefore no downgrade is possible

You can still jb 4.2.1 with redsn0w. it'll just be tethered.