Tested here and did work as expected. After giving ifconfig usb0 down/up the mac address didn't change and was also able to change the mac address with "ifconfig usb0 hw ether <mac>".
Tested here and did work as expected. After giving ifconfig usb0 down/up the mac address didn't change and was also able to change the mac address with "ifconfig usb0 hw ether <mac>".