As promised, the functionality is returning this week. Major Nelson announced as much this morning, noting that, like before, the boot to disc option will be accessible via System Settings on your Xbox's Dash -- users will be given a prompt for said update.
Additionally, this Thursday, an update will be applied to Gamercards on Xbox.com. As pictured to the left, the yellow and light grey of Gamercards past will be replaced by a new black and dark grey color scheme -- we're calling them "Gamercards at Night" -- and they'll lose their "zone information." With any luck, a smoking jacket and pipe will be added in the coming months. A Gamercard's gotta accessorize!