1: each update IOS system, iTunes will download the full firmware updates, on Windows, we can use iTools software such as Elsevier or the firmware download, but such software on OSX is not much class, is currently obtain more official firmware safe method is to use iTunes to download from the official server!
iOS firmware download folder location: / Library / iTunes / iPhone Software Updates
2: Black Apple friends, each looking for a complete dmg is a gripping thing, mostly at night is a third-party packaged clover version of Apple's official dmg original rarely, in fact, provided there is official Apple download, but do too low-key class
Download: https://support.apple.com/zh-cn/HT201260
