Update #3 : redsn0w beta should fix any APN or MMS issues that users were seeing. It’s safe to re-run it on an already jailbroken iPhone without restoring, Just deselect “Install Cydia” if you do that.
Download links : Mac OSX x86 , Windows
Update #2: redsn0w beta has been updated to clear many bugs that existed in the beta 4 version.
The download links for redsn0w 0.9.5b5-4 are:
Update #1: redsn0w beta has been updated to hacktivate iOS 4.0 for iPhone3G (in addition to jailbreaking the iPhone3G and iPod Touch 2G). The download links for redsn0w 0.9.5b5-3 are:
For now, the redsn0w beta release supports only the iPhone3G and iPod Touch 2G at today’s 4.0. It’s still a beta, so you’ll need to let Cydia reorganize, reload, and update after using redsn0w.
Reminder: iPhone3GS & iPod3G owners (especially if you used Spirit for your first JB) should stay away from iOS4 for now !!!
We will soon be able to jailbreak our iOS 4 devices using the latest version of redsn0w (0.9.5), it will enable all the new features of the iOS4. It will :
- Enable Baground Wallpaper
- Enable Battery percentage
- Enable Native Multi tasking
- Install Cydia
- And allows Custom Boot and recovery logo.
How to Jailbreak iPhone 3G iOS 4
Step 1: Make sure you have the latest version of iTunes installed (iTunes 9.2).
Step 2: Download iOS 4 for iPhone 3G to your desktop.
Step 3: Update your iPhone to iOS 4 via iTunes.
Step 4: Download RedSn0w 0.9.5b5-3 for Windows or Mac and launch it.
Step 5: Point RedSn0w to the iOS 4 you downloaded in step 2.
Step 6: Select “Install Cydia”.
Step 7: Follow the onscreen instructions.
Step 8: Let RedSn0w do the hard work for you. Once jailbroken, your iPhone will reboot.
That’s it!
Now as mentioned above, this is just a beta release of RedSn0w, which means you might have a few issues. One of the most common issues is that the Cydia icon appears all white. In order to fix this, simply add the following repo to Cydia and reboot your iPhone:http://apt.saurik.com/cydia-3.7.
If needed, you may now unlock your iPhone 3G running iOS 4 by following these simple instructions.
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[...] This post was mentioned on Twitter by Arjun, Arjun. Arjun said: Now on #techulus: redsn0w 0.9.5 for jail breaking the iOS4 http://bit.ly/96vSfD [...]
My problem is that cydia stucks on Downloading Packages
And wont do nothing 
Go to the Changes tab and refresh. After reloading data is completed, try to install redsn0w.