You can set the mac with 'ip link set dev wlan address $MAC'. But this is only a workaround. You could try to put this with your mac in init.hammerhead.rc for example, nd try if this works.
ifconfig wlan0 hw ether 00:90:4C:E1:87:FF
[Unit] Description=fixed_mac address [Service] Type=oneshot ExecStart=/usr/bin/fixed_mac [Install] WantedBy=multi-user.target