User:Nicolas17/IPSW formats

From The Apple Wiki

IPSW files have always been ZIP files, but the exact details of the format have changed over time, especially with respect to the root filesystem.

iOS version Rootfs DMG compressed in the ZIP DMG compression Root filesystem FS compression (decmpfs)
10.0.1-10.2.1 deflate UDZO HFS+ zlib (3/4)
10.3-11.? deflate UDZO APFS zlib (3/4)
11.?-12.5.7 stored UDZO APFS zlib (3/4)
13.0b2-13.7 stored ULFO APFS zlib (3/4)
14.0-15.7.2 stored ULFO APFS zlib (4) and raw (9)
16.x stored (but cryptex deflated) ULFO APFS zlib (4) and raw (9)