How can I change the OUI24 top part of the MAC address of eth0, to one of my own, while leaving the bottom device specific 24 bits to be same. I can see clearly that it appears Jessie's default behavior combines Raspberry Pi Foundation's OUI of b8:27:eb with that of the CPUINFO's least 6 digits into the full HWaddr.

Serial          : 0000000070813998
pi@raspberrypi:~ $ ifconfig eth0
eth0      Link encap:Ethernet  HWaddr b8:27:eb:81:39:98

I do know /boot/cmdline.txt supports smsc95xx.macaddr=.... Unfortunately this is on the SdCard. I wish to preserve the uniqueness to follow the Pi Hardware and not the SdCard.

I do not see a 70-persistent-net.rules. So not sure if possible or how to write a complicated udev rule here. I also don't see evidence of write_net_rules or how that would work on the Pi.

2 Answers 2


OUI is there for a specific reason, it identifies the manufacturer.

  • Yes, to create a unique network address, that does not over lap with others. Since I have my own OUI, this is not an issue. I am simply re-manufacturing the end product.
    – mpflaga
    Commented Aug 7, 2017 at 13:49

You cant change the MAC permanently in the hardware, its burnt in a ROM.

You can change the MAC from your OS, either by /boot/cmdline.txt or /etc/network/interfaces (Debian). And all these changes is on the SD card.

  • Yes, I had already stated your suggestions in the question as not being desirable.
    – mpflaga
    Commented Aug 7, 2017 at 13:50
  • I just clarified, MAC is burnt in ROM, can't be changed! And i noticed that you stated that the OS wasn't desired, but it is the you have to use.
    – MatsK
    Commented Aug 7, 2017 at 14:35
  • Actually I believe the Serial Number is burned into ROM, as a part of the CPUINFO and necessarily the MAC. Where it is clear the default MAC is a combination of this Serial Number and rPI's OUI on several of the units I have. So i conclude/assume they are not burning the same number in twice in two locations (e.i. CPUINFO and MAC). but rather when the default MAC is constructed it is from the CPUINFO and rPI's OUI. So I am looking for insight as to where and how this happens.
    – mpflaga
    Commented Aug 7, 2017 at 19:20

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