DeviceTree

The device tree is a representation of hardware used by the boot loaders (iOS's iBoot and OS X's boot.efi) to provide the kernel with a mapping of hardware. The tree is a hierarchical representation of devices by connection, somewhat similar to Solaris's device tree (/devices), and Linux's /sys/devices. It is used extensively by the boot loader, as it populates the various entries of the tree, and then passes it to XNU. XNU's platform expert then maps these addresses and uses them to communicate with the I/O buses and other low level hardware.

The device tree can be decrypted by the VFDecrypt keys. A program to dump the IMG3 file format, and in particular the device tree, can be found the companion website to Wiley's OS X and iOS internals book. A dump of the N88 device tree is here.