Apple released iOS 4.0.2 for iPhone and iOS 3.2.2 for iPad, patching the PDF security exploit, which also blocks browser-based jailbreaking by visiting JailbreakMe.com. For iPhone 3GS and 4G users, in case you are relying on jailbreaking and carrier unlocking, stay away from this update until jailbreaking tools are released.
Fortunately for iPhone 3G users, you can still jailbreak iPhone 3G iOS 4.0.2 using redsn0w by pointing to the older iOS 4.0 firmware ipsw file, here’s how.
0. Download the official iOS 4.0 firmware ipsw file for iPhone 3G, iTunes v9.2, and redsn0w .9.5b5-5.
1. make sure that iTunes v9.2 is installed, because redsn0w will depend on it.
2. Run redsn0w, click Browse and choose the 4.0 ipsw file, Click Next.
3. Select your jailbreak options. Make certain Install Cydia is selected; the other ones are optional. Verbose boot displays detailed boot information is generally preferred by developers and advanced users.
Tip: RedSn0w selected Enable Multitasking by default. If multi-tasking is not a must for you, we’d recommend un-check it as it makes iPhone 3G run very slow.
4. Please turn off your iPhone now and connect it to the computer, then click Next.
5. Follow the on-screen instruction to get into DFU mode.
6. Redsn0w will take care of the jailbreak process, once it’s complete you’ll be notified that RedSn0wis finished. Click the Finish button. When your iPhone finishes rebooting (5 minutes or so) it’ll be jailbroken.
That’s it.
Other Tips
1. For unlock users, update your ultrasn0w to v1.1-1 to save battery life, as iPhone Dev Team announced in Twitter:
“ultrasn0w upgraded to version 1.1-1 we’ve tweaked a few things that may help with standby battery life, you can upgrade via Cydia.
2. Although Apple has promised to investigating the matter of the new ios 4.x slowing iPhone 3G down, there’s no confirmation that ios 4..2 has fixed this. If you are experiencing slow performance with your iPhone 3G in the ios 4.x, disable Spotlight by going to Settings- General -Home – Search Results, and turn off everything you don’t need.