Xcode 4.2 + LLVM 3: unable to run on iPhone3G

Just installed Xcode 4.2 for Snow Leopard and started to developer a new project. The开发者_开发技巧 app successfully runs on iPhone4 but isn't on iPhone3G. The code gets build, compiled, ran and finished. I just get a message "Finished running ...". Here's the settings that I have set both on Project and Target Build settings:

Build otions->GCC_VERSION = Apple LLVM 3

Architectures->ARCHS = "armv6 armv7" Architectures->SDKROOT = "Latest iOS5"

Deployment->IPHONEOS_DEPLOYMENT_TARGET = "iOS 3.1"

Linking->OTHER_LDFLAGS->Debug->Any architecture |Any SDK = "-ObjC -all_load"

Any ideas or suggestions what else should I try?

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This problem appears to happen when creating new projects with Xcode 4.2. When creating such projects, Xcode adds one hidden key in app plist file, that restricts device to run on armv7 architecture only. You need to delete that key. Also, you need to replace "standard (armv7)" to "armv6 armvv7" value in ARCHS build setting, both in project and targets build settings. And also to check ONLY_ACTIVE_ARCH is set to NO.

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I have seen 'finished running...' in my code too with an iPhone 4. Whenever that happens, I do a clean build and also uninstall the app from my iPhone. Post that, things start working again.