iPhone Atlas warns that the 1.1.3 jailbreak may prevent official third party apps from working.
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/iPod Touch. This gets damaged by the jailbreak, although it’s reversable. It does mean that official and unofficial third party apps won’t be able to co-exist.
Since there’s an official SDK coming soon, which will be available to everyone, there’s no reason the developers currently writing unofficial applications won’t switch to the SDK and release the same applications in a form that won’t require jailbreaking the iPhone.
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