How to Downgrade iPhone OS 3.1 to 3.0 for iPhone 2G 3G 3GS

ev team already warned don’t upgrade to 3.1 and wait for next version of Pwnage Tool to preserve your baseband. Upgrading to 3.1 with Ultrasn0w installed will cause people to lose Ultrasn0w and will be unable to get it back. OS 3.1 contains a baseband update 5.11.04 BB for iPhone 3G and 3GS. The latest Modem Firmware 5.11.04 BB which is not down gradable. So if you accidentally updated your iPhone 2G, 3G or 3GS to OS 3.1 here is the handy guide for downgrading. Remember this will not downgrade your baseband only your firmware will be downgraded. It’s possible to downgrade OS however we strongly suggest you to carry on with OS 3.0 until Dev team releases Pwnage Tool.

Update for iPhone 3GS : So as of today, Apple has stopped signing 3.0 and 3.0.1 restore files. That means that if you have a 3GS iPhone you cannot restore any firmware other than 3.1. If you are happily jailbroken today and something goes wrong you are pretty much screwed. So this means you can’t downgrade even your OS from 3.1 to 3.0, Thanx to Saurik for making iPhone 3GS Downgrading possible. Follow the link below for our new guide.

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