Ubuntu server images needs random MAC address

How do I get a random MAC address for my devices?? They all have the same MAC!!

I tried messing with the .dtb generated in the SD folder: BPI-M4-bsp/SD/bpi-m4/BPI-BOOT/bananapi/bpi-m4/linux

even the base .dtsi file in local archive BPI-M4-bsp/linux-rtk/arch/arm64/boot/dts/realtek/rtd139x/rtd-139x.dtsi

no luck. Anyone able to set their MAC address automatically?