You can "JTAG" your xbox 360, but there are a few things bad about it.
First, it's illegal to play copied CD's.
Second, if you JTAG or flash your Xbox, it automatically voids your warranty. If your Xbox crashes, you can send your Xbox back to Microsoft and they'll fix it for free (not warranty). If they see that you flashed or JTAGed your Xbox, they won't fix it for free.
But, there are alot of good things about JTAGing, being able to play burnt games is one of them. Look 'em up if you want more info.