The FBI recovered iCloud backups from one and a half months before the shooting, and wanted to access encrypted files on the device.

Main article: FBI–Apple encryption disputeĪfter the 2015 San Bernardino attack, the FBI recovered the shooter's iPhone 5C, which belonged to the San Bernardino County Department of Public Health. Without SHSH blobs, the device will refuse to restore, thus making downgrades very difficult to achieve. īist is sent to Apple's TSS server and checked in order to obtain SHSH blobs before every restore.

There are two more files named 'ist' and 'ist', both property lists that contain compatibility information and SHA-256 hashes for different components. bbfw format (renamed zip file), and other firmware files. The file also holds the kernel caches, and a 'Firmware' folder which contains iBoot, LLB (Low-Level Bootloader), iBSS (iBoot Single Stage), iBEC (iBoot Epoch Change), the Secure Enclave Processor firmware, the Device Tree, Firmware Images (Apple logo, battery images, Recovery mode screen and more), baseband firmware files in. tvOS, audioOS and macOS also include a disk image for the recovery environment (recoveryOS). ipsw file itself is a compressed archive file (renamed Zip archive) containing at least three Apple Disk Image files with one containing the root file system of the OS and two ram disks for restore and update. Users can flash Apple silicon Macs through Apple Configurator 2.

All Apple devices share the same IPSW file format for iOS firmware and their derivatives, allowing users to flash their devices through Finder or iTunes on macOS or Windows, respectively. IPSW, iPhone Software, is a file format used to install iOS, iPadOS, tvOS, HomePod, and most recently, macOS firmware for devices equipped with Apple silicon.

Ipsw file