CAUTION: Do not even try to flash retail Xbox 360s with these developer binaries.
Only the developer Xbox 360s are capable of "restoring to a version of the Dashboard".
The developer Xboxes cannot run, read and execute any retail signed code and cannot
connect to Xbox LIVE. They are meant to be used for development and testing of
unreleased software for the Xbox 360 platform purposes only, under a signed strict
non-disclosure agreement (NDA). If you try to flash a retail Xbox 360 with thesse XDKs,
you have the risk to brick it, i.e. render it unusable, and no support can be given to
that console anymore afterwards. You are doing all the actions at your own risk.