Disable Random MAC Address on g_ether (and g_cdc)
Add or update the file
/etc/modprobe.d/g_ether.conf
with the following line:
options g_ether host_addr=00:11:22:33:44:55
For g__cdc replace g__ether.
From: http://linux-sunxi.org/USB_Gadget
Enrique CR - 2016-11-07