How to undo the jailbreak

[jasoncloudie]

I need to undo the jailbreak I did on my iPad, and I keep getting an error message in iTunes when I hit "restore" for my device. It says it "isn't eligible for the requested build". What am I doing wrong

 

[f4780y]

Sounds like you might still have your hosts file pointing at Cydia or localhost after the jailbreak. You need to point back towards Apple...

 

[jasoncloudie]

How do you change that? I don't know how to fix that

 

[Ksane]

Are you sure you're not trying too install 4.3 beta without your UDID registered? That's what it sounds like to me as that's the only time I got that specific error code. I updated to 4.3 fine (after registering my UDID) but it won't allow me to downgrade to 4.2.1 even though I have blobs saved. I can only downgrade to 3.2.1 or 3.2.2
Mine is a 3G iPad, is that what yours is?

 

[f4780y]

Are you on windows or Mac, and did youuse tinyumbrella at all?