iphone 3g

[1greenmick1]

how can i restore back to 3.21 firmware
from 4.2 back to my iphone

[deggers316]

go into dmu mode
paste this link it will show you
http://limitededition...iphone-into-dfu-mode/

[jeffmatt]

You may refer to this guide, it's about how to downgrade iPhone, it works pretty well for me.
http://www.reviewstow...en-ios4-and-ios3.html
Hope it helps. Contact me if you have any other question.