Change MAC address Android using ip link?
As superuser run:

# netcfg


A list with the interfaces will appear. For example my interface was eth0

# ifconfig eth0 down
# ifconfig eth0 hw ether your:new:mac
# ifconfig eth0 up


Note that not all drivers support this operation, and the Android ifconfig do not support these commands. You will need another ifconfig executable, perhaps that from busybox will be suitable. 

After the reboot these changes are lost.