IPSW File Format

IPSW (iPod¹ SoftWare) Files have the Magic Number 504B0304 (PK\003\004) and thus are ZIP Archives. They can be modified with typical zip/unzip tools (i.e. change extension to .zip and double click). An IPSW File is used to deliver the iPod Touch / iPhone firmware to the end-user.

¹The IPSW files are used starting from the iPod 1G, even though they have a different format than iOS-based devices.

IPSW Contents

root folder

• Restore Ramdisk
• Update Ramdisk (Firmware 1.0 didn't contain an Update Ramdisk as there is no official firmware to update from)
• Filesystem Ramdisk (the largest .dmg file)
• kernelcache.release.XXXXXXX file (application processor specific i.e S5L8900, S5L8920, S5L8720, S5L8922, S5L8930)
• BuildManifest.plist (first appeared in firmware 3.0, I guess)
• Restore.plist file

• \Firmware (Folder)

Firmware Folder

• \all_flash\all_flash.XXXXX.production (Folder - hardware specific i.e. M68ap, N82ap, N88ap, N45ap, N72ap, N18ap, K48ap)
• \dfu (Folder)
• ICE3_XX.XX.XX_BOOT_02.06.Release.bbfw (Contains the baseband and the bootloader. X stands for a number. This is the baseband version. 02.06 ist the bootloader. Only in the iPhone 4 firmware.)

all_flash.XXXXX.production Folder

• IMG2/IMG3 files
• manifest

dfu Folder

• iBEC.XXXXX.DFU (hardware specific i.e. M68ap, N82ap, N88ap, N45ap, N72ap, N18ap, K48ap)
• iBSS.XXXXX.DFU (hardware specific i.e. M68ap, N82ap, N88ap, N45ap, N72ap, N18ap, K48ap)
• WTF.XXXXX.DFU (hardware specific i.e. M68ap, N82ap, N45ap, N72ap - currently not present in firmwares for the iPhone 3GS and later, because it is mostly used to patch issues with the DFU mode that was burned into the bootrom)

Example

This is a ls -alR of an extracted iPhone 3GS 3.0 Firmware IPSW.

total 608400
drwx------@ 11 m  staff        374 17 Jun 07:11 .
drwxrwxrwx   5 m  staff        170 18 Jul 07:34 ..
-rw-r--r--@  1 m  admin  281214976 22 Mai 17:10 018-5302-002.dmg
-rw-r--r--@  1 m  admin   12769604 22 Mai 16:59 018-5304-002.dmg
-rw-r--r--@  1 m  admin   12777796 22 Mai 16:59 018-5306-002.dmg
-rw-r--r--   1 m  admin      21097 22 Mai 17:29 BuildManifest.plist
drwxr-xr-x@  5 m  staff        170 17 Jun 07:11 Firmware
-rw-r--r--   1 m  admin       1763 22 Mai 17:10 Restore.plist
-rw-r--r--@  1 m  staff    4695492 22 Mai 14:32 kernelcache.release.s5l8920x

./Firmware:
total 16
drwxr-xr-x@  5 m  staff   170 17 Jun 07:11 .
drwx------@ 11 m  staff   374 17 Jun 07:11 ..
drwxr-xr-x@  4 m  staff   136 18 Jun 02:10 all_flash
drwxr-xr-x@  4 m  staff   136 22 Mai 13:39 dfu

./Firmware/all_flash:
total 16
drwxr-xr-x@  4 m  staff   136 18 Jun 02:10 .
drwxr-xr-x@  5 m  staff   170 17 Jun 07:11 ..
drwxr-xr-x@ 16 m  staff   544 22 Mai 13:43 all_flash.n88ap.production

./Firmware/all_flash/all_flash.n88ap.production:
total 1320
drwxr-xr-x@ 16 m  staff     544 22 Mai 13:43 .
drwxr-xr-x@  4 m  staff     136 18 Jun 02:10 ..
-rw-r--r--@  1 m  staff   44996 22 Mai 13:08 DeviceTree.n88ap.img3
-rw-r--r--@  1 m  staff   67908 22 Mai 13:12 LLB.n88ap.RELEASE.img3
-rw-r--r--@  1 m  staff    9604 22 Mai 13:15 applelogo.s5l8920x.img3
-rw-r--r--@  1 m  staff   19716 22 Mai 13:15 batterycharging0.s5l8920x.img3
-rw-r--r--@  1 m  staff   24900 22 Mai 13:16 batterycharging1.s5l8920x.img3
-rw-r--r--@  1 m  staff   76100 22 Mai 13:16 batteryfull.s5l8920x.img3
-rw-r--r--@  1 m  staff   56772 22 Mai 13:16 batterylow0.s5l8920x.img3
-rw-r--r--@  1 m  staff   65348 22 Mai 13:17 batterylow1.s5l8920x.img3
-rw-r--r--@  1 m  staff   20356 22 Mai 13:17 glyphcharging.s5l8920x.img3
-rw-r--r--@  1 m  staff   19332 22 Mai 13:18 glyphplugin.s5l8920x.img3
-rw-r--r--@  1 m  staff  178500 22 Mai 13:21 iBoot.n88ap.RELEASE.img3
-rw-r--r--@  1 m  staff     341 22 Mai 13:43 manifest
-rw-r--r--@  1 m  staff   20484 22 Mai 13:24 needservice.s5l8920x.img3
-rw-r--r--@  1 m  staff   47876 22 Mai 13:24 recoverymode.s5l8920x.img3

./Firmware/dfu:
total 416
drwxr-xr-x@ 4 m  staff     136 22 Mai 13:39 .
drwxr-xr-x@ 5 m  staff     170 17 Jun 07:11 ..
-rw-r--r--@ 1 m  staff  104772 22 Mai 13:30 iBEC.n88ap.RELEASE.dfu
-rw-r--r--@ 1 m  staff  104772 22 Mai 13:36 iBSS.n88ap.RELEASE.dfu