How to develop for original "iPhone" with latest SDK?

I've seen similar questions to this but not too many definitive answers...

I used to have a version of Xcode (not sure where I got it) that would only target iPhone OS 3.1.3 devices and since I like to work with the least common denominator, this was cool with me. Recently I upgraded to the latest SDK so I can test my code on OS 4 as well. Now the lowest iPhone OS target I have is 3.2 but I have the original iPhone and according to iTunes 3.1.3 is the latest version for that device.

So right now I can't upgrade my phone to 3.2 and I can't set my target in Xcode to 开发者_Go百科3.1.3. What do I do? Should I reinstall the old SDK but at a different path?

It seems like Apple is trying to phase out the original iPhone altogether but that seems absurd to prevent developers from targeting a device that clearly still has it's place in the market.

Thanks

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In your target and project settings, in your Build configuration, set the Base SDK to 4.0, then scroll down and set the iPhone OS Deployment Target to 3.1.3. Installs apps just fine on my old 3.1.3 devices.