The developers of the Redsn0w jailbreak utility for iOS have released a new version that can jailbreak most devices running Apple iOS 4.1. Redsn0w 0.9.6b2 uses the recently launched limera1n exploit, but it also has a few extra features including the ability to install a custom boot logo or enter DFU mode ins PwnageTool to install custom firmware on your device.
Redsn0w can be run from Windows or OS X, and lets you jailbreak the following devices:
- iPhone 4
- iPhone 3GS
- iPad
- iPod touch 3rd or 4th generation
- Apple TV2nd generation
You can find download links and more details at the iPhone-Dev team blog.
via The Apple Blog
The easiest way to update an iPhone 4 without updating the baseband is to use TinyUmbrella.
Everything you need to know about iPhone 4 :http://www.aneesoft.com/tutorials/iphone/index.html