Tutorial:Creating a NOR-only IPSW

From The Apple Wiki

This will create an IPSW that only flashes your device's NOR. It will not touch the operating system or NAND.

  1. Create a custom IPSW
  2. Unpack it, remove rootfs DMG
  3. Decrypt the ramdisk (xpwntool) and mount it.
  4. Edit options.plist (/usr/local/share/restore/options.plist) on the restore ramdisk:
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
  1. Unmount and reencrypt the restore ramdisk.
  2. Repack the IPSW.

NOTE: This technique only works on devices that have an untethered bootrom exploit (Pwnage or 0x24000 Segment Overflow).