I've been trying to get my app - built in Xcode 4.2 in Snow Leopard, using ARC, targeting iOS 4.0 and up - to install on a 3G, with no luck. I've tried every solution I can find (like this thorough one here: Is it possible to target older iOS versions when using Xcode 4.2 and iOS 5 SDK?) and while I've been able to get the app to run on the phone via Xcode, when I share the app and try to install it through iTunes, I keep getting the same error telling me the app was not installed because it is not compatible with this iPhone. My client is using a 3G so this is a pretty big problem.
I've set the architectures / valid architectures to support armv6 as well as armv7 in my build settings and I've deleted the line in info.plist about the required device capabilities with armv7 (I also experimented with adding armv6 instead of deleting the line, which made no difference). I also added the -mno-thumb to Other C Flags in case that was the issue. Even though I know for a fact that it works on a 3G, iTunes refuses to install it. Is there something I'm missing?