iPhone TIPS: 1.1.3 jailbreak may kill official iPhone SDK apps

You might want to think twice about applying the current iPhone 1.1.3 jailbreak “soft-update” that was released by “Nate True” We’ve received word that the method may prevent installation of official third-party applications that will be created by the forthcoming iPhone SDK (software development kit) from Apple. The reason: this jailbreak method breaks “Nikita,” a component that is responsible for installing signed software. It appears that the current process is reversible, but almost certainly won’t be able to co-exist with official third-party apps.
iPhone firmware 1.1.3 includes a mechanism for approving signed applications. Signed apps use private keys to authorize themselves for installation on the iPhone and iPod Touch. The first group of applications to use this mechanism is the $20 iPod Touch application (Mail, Notes, etc.) upgrade available for purchase through iTunes.
source iphoneatlas.com