can't change mac address please help !

[Chairmansaab]

Hey guys,

I tried changing mac address by following command

ifconfig br0 down hw ether Aa:bb:cc:dd:ee:ff:ee

whenever i type this command it stop responding
i can't get it up via this command.

ifconfig br0 up

please help i will appreciate !
Thanks

[haqking]

sudo ifconfig br0 hw ether aa:bb:cc:dd:ee:ff:ee

or

sudo ip link set br0 address aa:bb:cc:dd:ee:ff:ee

[Chairmansaab]

sudo ifconfig br0 hw ether aa:bb:cc:dd:ee:ff:ee

or

sudo ip link set br0 address aa:bb:cc:dd:ee:ff:ee

i am using telnet on both of my GALAXYS2 (ANDROID) and my windows 7 lappy.
i can't seems to change it
I have broadcom chipset in my modem > model name BCM96338 if that matter
here is screenie of the error

and i tried second command too i am getting dev is duplicate and address is garbage
thanks for reply