Ive read some threads that say its not possible but i would think that if you have full access to your emunand you might be able to change it with a custom system app. if youre gonna ask me why its for bypassing internet blocking and such if you get blocked on your internet, also you might want a different mac address for other reasons that i dont care about but could be useful. If its possible i think someone should make a tool that can change your mac, it might be useful.