After the iPhone 4G design specs are made available, the Chronic Dev Team will working diligently to prepare a jailbreak solution for the public. The Chronic Dev team prepared for the iPhone 4G jailbreak, without having the device in their hands yet.
The jailbreak solution will be a “Userland” exploit, this is a methond of jailbreaking through modifying commands existing outside of the iOS kernel. Popular browser based userland exploits such as the three versions of the popular JailbreakMe solution, patch iDevices at a software level to jailbreak them. Boot exploits allow for low-level control.
The biggest downside of a exploit that is userland based is that Apple can easily patch it and has been doing so promptly.