I have this jailbroken iPhone 3G with iOS version 4.2.1 (the latest supported version). When I connect it to Xcode 4.2, Xcode starts copying the debug symbols. It stops copy
Error in Xcode getting debugging info from 5.0.1 iphone
solved, see the link to archive with iOS5.0.1 debug info
download & unpack to "~/Library/Developer/xCode/iOS DeviceSupport/" & be happy =)