Installed Xcode 4.2, now can't install apps to iPhone 3G

[SimonM]

I have just upgraded from Xcode 4.1 to 4.2. Now when I try to run apps that previously worked on my iPhone 3G, nothing happens. When looking at the console in organizer the following error is reported a number of times:

'Could not receive USB message #6 from Xcode. Killing connection'

The same app installs and runs fine on my iPod touch which has iOS 5 installed. But I just can't get it to run on the iPhone 3G with iOS 4.2.1. I have changed the Deployement Target to 4.2 (which is all I had to do in the past to get apps working on this older phone). I think the problem has to do with the only architecture I can select in Build Settings is armv7, there is no option to select armv6.

Has anyone any suggestions on how to get Xcode 4.2 to work with an iPhone 3G?

Thanks.

[JasonR]

Just manually add armv6 to the Architectures setting, and it seems to work fine on my old iPod Touch. I'm pretty sure the 3G works the same.

[revg]

JasonR is correct and in case you need more detailed instructions here is a valuable link

iphone - Possible to target older iOS versions when using XCode 4.2 and iOS 5 SDK? - Stack Overflow