Orange Pi Win Plus - Permanently changing MAC address

Hi guys,

I've been busting my head for days now trying to find a way how to permanently change MAC address on my ehternet on Opi Win Plus boards but nothing yielded positive outcome.

The reason I need to permanently change MAC address is because I'll be running 6 of these boards on the same network and since all of them have identical MAC it's impossible for my router to manage them properly.

I'm running Ubuntu_xenial_default_3.10.107_server with legacy kernel.

I've tried changing the /etc/network/interfaces file by adding hwaddress ether xx:xx:xx:xx:xx:xx , changing from static to dhcp and doing all sorts of combinations in hopes that something will work. After every change I was restarting the board and the router so they would force new changes. Nothing.

I've also tried changing it with macchanger but that didn't do the trick as well.

One thing is not clear to me though - should there be any files in /etc/network/interfaces.d/ since at the beginning of my interfaces file it says source /etc/network/interfaces.d/* which led me thinking that this file is trying to call other files from that folder. Is this true?

And than I've stumbled upon several posts saying that MAC addresses are somehow hard coded into the system and that one of the potential solutions would be to decompile dtb files, changing it there and compiling it back.

These are the forum topics I've found:

https://forum.pine64.org/showthread.php?tid=2078&pid=19149#pid19149

https://forum.armbian.com/topic/4059-orangepi-one-mac-address/?tab=comments#comment-29767

https://forum.armbian.com/topic/3419-mac-address-assignment-on-orange-zero/?tab=comments#comment-27200

https://forum.armbian.com/topic/1738-opi-lite-mac-address/?tab=comments#comment-15574

Can anybody help me out with these steps?

I really don't know where to even start looking for these files which need to be decompiled and changed.