ImageBuilder; Cannot upgrade OS running on eMMC

NanoPi 5rc router.
From what I'm reading, there is no point in using hexdump after the router is up and running because that's only showing runtime info.

I need to find a way to get deeper into the hardware but from the openwrt command line so I could dig that MAC's out and set those in the network file and do this automatically if I re-flash the device.

Who's great idea is it to constantly change MAC? Is this the future? What a mess it causes.