Just a small observation here. This doesn’t effect functionality in any way, but when you jailbreak, you get a little firecore logo on the lower right corner of your aTV wallpaper. After you install aTV Flash (black) the default wallpaper is restored, removing the FC logo. I don’t know if this was by design, but I figured it was worth mentioning.
Yes, the FC logo is just used for indicating the AppleTV has been jailbroken.
The default image gets restored when installing Maintenance, nitoTV, or XBMC.