I've updated my iPhone 3G to the latest version (4.1 8B117), but I'm still missing features such as the task manager, background wallpaper, etc. I've tried restoring it a couple times now, even set it up as a brand new phone, but I'm still missing these features. Can anyone shed some light on why this is?
The features you mentioned, "task manager & background wallpaper" are not available on the iPhone 3G. In order to have access to all the features of iOS 4 you need to have it installed on an iPhone 3GS or later.