Error trying to push a build to a first gen iPod running os 3.1.3 using SDK 4

I just upgraded to iPhone SDK 4, I was building to the iPod running OS 3.1.3 fine untill i ugraded the SDK. When I try to build now I get the following error:

Can't run 'AppName' - was built for 'armv7', but device requires 'armv6' or compatible architecture.

In the project settings I have set开发者_开发百科 the Architectures to Standard (armv7 armv6), and set the Base SDK to iPhone Device 4.0. I also set the iPhone OS Deployment Target to iPhone OS 3.1.3.

Any ideas what might be going wrong on me?

Fixed it. I changed the project settings but also had to change the active target settings. This is done in Project -> Edit Active Target "appName". I just had to switch the Architecture from optimised to standard.