The iPod works in three modes: Normal Mode - How to use the iPod works Normal Recovery Mode - This mode is induced to update or restore iPod, the OS does not load, just a few basic routines to allow recovery. You can exit this mode in many ways, without restoring. DFU Mode - Device Firmware Update: It's a way to q the device to upgrade / downgrade firmware is induced. You say a method to lowest level q recovery mode. In this way even charge less and less code routines. As an Simil, q may not be real, the recovery mode depends on the OS for recovery, and is the same OS who manages it. The DFU mode would manage the bootloader, then the restoration would be completely agena the OS. This is not true, but you can understand a little better.