Originally Posted by f4780y

Guys, guys, guys.... SO MUCH MISINFORMATION AND PARTIAL TRUTHS!

You can ONLY downgrade or upgrade to an IOS version OTHER than the current version being provided by Apple (currently 4.3) by having saved SHSH blobs for the version you want to install.
Just downloading the IOS version you want from the internet and shift / option-restoring in iTunes WONT WORK. Apple has a security system which cannot be bypassed and requires a signature from apples servers which is particular to your device alone. The only workaround is to save your unique signatures as Apple makes them available to you. There is a window of opportunity only whilst Apple is providing the signatures for the current IOS. The window for 4.2.1 was closed just after 4.3 was released.
You can save them either using Cydia's "make my life easier" feature and / or Tinyumbrella on your PC.
If you don't have saved SHSH blobs for 4.2.1 for your device then it is IMPOSSIBLE to install 4.2.1, no matter what you do or what version of IOS you are currently on.

In the OPs situation, without saved SHSH's for 4.2.1 he cannot upgrade from 4.2 to 4.2.1. The only option is to go to 4.3 or stay on 4.2.

Hope that helps.

I meant you can still downgrade. Apple hasn't killed the 4.2.1 shsh yet. I upgraded to 4.3, realized it is lame and you can't jailbreak and downgraded the next day. And i didn't have any shsh saved. And this was a couple days after iPad 2 was released. So before you go telling everyone they are wrong, do a little research. Apple never kills the shsh immediately.

Actually the SHSH have not been supplied by Apple for several days now. Confirmed. I do my research mate. I am an Apple developer and keep a very close eye.
Google it, you will see plenty of people complaining that the window is closed for 4.2.1 and they missed it. Try and pull them yourself now. Fail? I think so.

Originally Posted by grayshark95

Originally Posted by molk958

You can update to an old ios, howev it is only, as far as i am aware, possible through the redsn0w jailbreak

Actually you can update to an older iOS, but it has nothing to do with redsnow. You just have to download 4.2.1 from a website or get it from a friend since apple will only let you download 4.3

Really, you want to get into this with me? Downloading a old version of IOS is not just what he as to do... Get your facts right BEFORE you criticise me for providing irrefutable facts and truth...

Oooh, I was right. Apple never kills the shsh immediately. And chill dude.....

Originally Posted by grayshark95

Oooh, I was right. Apple never kills the shsh immediately. And chill dude.....

I think the attitude came from you dude. Re-read your post, your criticism was of my advice... I am chilled.

Need more facts? iOS 4.2.1 signing is really closed - 12th March http://thefirmwareumbrella.blogspot.com/
That's 5 days ago. Big enough of a man to admit you were wrong?

Originally Posted by f4780y

I think the attitude came from you dude. Re-read your post, your criticism was of my advice... I am chilled.

Need more facts? iOS 4.2.1 signing is really closed - 12th March http://thefirmwareumbrella.blogspot.com/
That's 5 days ago. Big enough of a man to admit you were wrong?

I believe you, so I just made the window. As for being a man, I feel like I am in jr. high with that sentence.

And the iPad forums family is back together again.

Okay you two! You can both chill. Please?

Originally Posted by SweetPoison

Okay you two! You can both chill. Please?

Oh we are done. That is what I meant by going over every now and then.

It's cool. You both know so much and are such a great asset to IPF ~ let's keep it that way, okay?

So I think we answered the thread's question, so I'm done here.