iSHSHit is a new application for jailbroken iPhone users that allows you to backup device firmware SHSH blobs from Apple directly on your device for later downgrading. It automatically uses the Cydia On File service in the background, so it’s a great way to ensure that your SHSH is stored by Cydia. iSHSHit can also email your SHSH blobs to you for more permanent storage. You can download iSHSHit for free in the Cydia Store via the BigBoss repo. » Backup Your Firmware SHSH Blobs Using iSHSHit [jailbreak]

Bigboss has warned that non developers should not install the new iPhone 3.0 OS. The beta firmware is only meant for developers and installing it on a live iPhone could cause some serious problems. Hit the break to see why.
» iPhone OS 3.0 Beta: Do not use

Apple’s iPhone OS 3.0 Beta pre-installation advisory document states that once you’ve updated a device it will be in a locked state with no way of going back to an earlier firmware. Well Ralf Rottmann has tried after restoring Beta 3.0 to downgrade his 2G iPhone back to 2.0.
Check out after the break how he did it.
» Downgrading & unlocking iPhone OS 3.0 is possible!

The iPhone DevTeam have posted another entry on their blog, this time showing how they successfully downgraded the iPhone 3G’s baseband. This isn’t an unlock, but it’s definitely progress. Read more for the blog entry. » iPhone DevTeam successfully downgrades iPhone 3G baseband.