Most of the "answers" here either don't care or don't know what you're talking about. The same thing happened to me this morning after a software update on my HR44. The wired ethernet mac address of the Genie changed -- by the last digit, and "broke away" from its static IP as I assigned in my router and received a new dynamic IP.
Any thoughts would be appreciated. But we don't need advice on where to find the mac address, discussion of minis, explanations of wireless mac addresses, MoCA mac addresses, or other noise that has nothing to do with the issue. Please try to understand the question and stick to it. The hardwired ethernet mac address, as reported to the rest of the world by the Genie, changed by a digit, and the question is why. If you can be of any help, thanks.