Downgrading from 4.3 to 4.2.1 on 3GS

[flatlined#IM]

I did the update to 4.3 and would like to go back to 4.2.1, Has anyone done it? From what I've read I download a copy of 4.2.1 of for the 3GS, which I Did ,place it on your desktop, while connected and in itunes hold the shift key and press restore, you will be able to browse to firmware, select the copy of 4.2.1 and let itunes restore. Also I downloaded tiny umbrella incase I got an error 1015.

Has anyone else done this?

Thanks

 

[Garz]

I dont think itunes will verify 4.2.1 anymore. Also, I think 4.3 brought a new baseband so doubt it will work for both those reasons

 

[big9erfan]

Apple stopped signing 4.2.1, unless you saved your SHSH blobs you won't be able to downgrade. Even if you could downgrade, you would get some error codes as it cannot downgrade the baseband.