Restoring iPhone 3G to iOS 3.1.3?

[johnmc]

Hello,

I was told by AT&T to restore the device to complete the unlocking process. When I try to restore in iTunes, I'm informed that iTunes will restore and upgrade my iPhone to iOS 4.2.

I've read everywhere that iOS > 4.0 slows up iPhone 3G. So, I'd like to:

1. Restore my phone and get it unlocked.

2. Run iOS 3.1.3.

Will following this guide accomplish my above goals?

How to Downgrade Your iPhone 3G from iOS 4 to iOS 3.1.3

If not, could the experts here please advise on how I should go about doing it? I'd really appreciate any input on this.

Thanks a ton in advance.

 

[willerz2]

Still a valid guide for the iPhone 3g

 

[johnmc]

Still a valid guide for the iPhone 3g

Thanks a lot, willer..

I followed the link that I posted and everything was alright: