I have a very odd one I found today. I built a Sencha based app and it runs fine on all iPhones tested except iPhone 3G and OS 4. All other setups appear to work fine. Note that in a browser it works fine on the phone, just not as an app.
So I decided to use the console to find out how far it gets. I have a main panel with about 10 cards inside it for interface. I added some debug.log() statements (phonegap) and ran the simulator. It all stopped working on the main screen just like the 3G was doing. Upon MUCH more testing it seems that any calls to debug.log() will log the line but also seems to destroy my UI. It just goes blank. Anyone seen anything like this before?