The file extension IPSW is associated with Apple devices which run on the iOS operating system. The devices include the iPhone, iPod Touch, and iPad which also connect with iTunes. iTunes is a digital media application which provides a way to purchase, play, and organize digital music and video files. Apple devices also use the iTunes server to receive updates and other data from IPSW files.
The IPSW file extension is categorized as a compressed archive file type which contains updates and installation files for the iOS operating system. IPSW files are encrypted and stored as a DMG Apple disk image which is a proprietary file designed solely for use with Apple devices. DMG files are similar to the ISO file which is used with the Windows operating system.
Only the latest IPSW files are stored by iTunes since Apple devices which run on iOS can only be updated or changed back to the factory default settings. iOS devices cannot be changed back to older versions of iOS; however, the contents of different versions of IPSW files that contain DMG images can be obtained on different servers. The servers are accessed by iOS users who use jailbreaking applications to add third party applications to an Apple device. Jailbreaking an iOS device removes the limitations created by Apple and allows users to access the entire UNIX file system.
How to Open IPSW Files
The most common method used for opening the file extension IPSW is by using the Apple iTunes service. iTunes is available for download on the Apple website and is compatible with the Windows operating system and Mac OS X.
IPSW is a compressed file type, which means the file can be opened using a compression utility program which supports the ZIP file format. The file extension must be changed to the ZIP extension and then opened using a compression utility such as Apple Archive Utility, which is a default archive utility included in Mac operating systems. You can also use a Mac compatible compression utility such as StuffIt Deluxe which is available as a 30-day free trial on the SmithMicro website.
Since IPSW store encrypted DMG Apple disk images, once you open the IPSW file using a compression utility, it is necessary to use a decryption tool to access the contents of the DMG file. VFDecrypt Keys can be used to decrypt a DMG file which accompanies the firmware updates in the file extension IPSW. VFDecrypt Keys is available on the iPhone Wiki website.
IPSW files can also be opened using Pwnage Tool, which is a software application that provides tools for jailbreaking an Apple device to access the UNIX file system. Pwnage Tool is available on the iPhone Development Team website at iPhone-Dev.org. If you are using the Windows operating system, IPSW files can be accessed using redsn0w which also works with Mac OS X. Redsn0w is a jailbreaking application which is available on the iPhone-Dev.org website as well.
To locate IPSW files on a Mac device the file path is: Users/<UserName>/Library/iTunes/<iOS device> Software Updates/. For the Windows operating system, IPSW files are located by following the file path: Users\<UserName>\AppData\Roaming\Apple Computer\iTunes\<iOS device> Software Updates.
Keep in mind if you jailbreak an iOS device to add third party applications, Apple may not honor the device warranty if something happens to the device.