How to keep the same MAC address after consecutive build and flash operations

RE: How to keep the same MAC address after consecutive build and flash operations

Amanda Hsieh — Thu, 04 Dec 2025 20:25:55 GMT

It will be erased.

RE: How to keep the same MAC address after consecutive build and flash operations

gc0rreiab — Thu, 04 Dec 2025 17:39:13 GMT

What is the expected behavior if the flash memory is erased in the middle of a flashing operation? For example, what happens when I use the Erase Board function while an nRF54L15 DK is connected to my laptop? Will the persistent IEEE 802.15.4 Extended Address be erased and regenerated?

RE: How to keep the same MAC address after consecutive build and flash operations

Amanda Hsieh — Wed, 12 Nov 2025 16:34:38 GMT

That's correct.

RE: How to keep the same MAC address after consecutive build and flash operations

gc0rreiab — Wed, 12 Nov 2025 11:06:59 GMT

If I understand correctly, the IEEE EUI-64 address is a globally unique identifier assigned by the IEEE Registration Authority and consists of a 24-bit Organizationally Unique Identifier (OUI) and a 40-bit unique extension. Nordic Semiconductor likely purchases a block of these addresses and programs one unique EUI-64 into each nRF54x device during manufacturing.

The IEEE 802.15.4 extended address, on the other hand, is a 64-bit MAC address used in IEEE 802.15.4 networks (such as Thread or Zigbee) and it is typically derived from the EUI-64 either by hardware or during software stack initialization. This means the IEEE 802.15.4 extended address can change between resets or reinitializations unless it is explicitly stored and made persistent?

RE: How to keep the same MAC address after consecutive build and flash operations

Amanda Hsieh — Tue, 11 Nov 2025 18:24:53 GMT

Hi,

Do you mean the IEEE 802.15.4 extended address or the IEEE EUI-64 address? Check this post.

otLinkGetExtendedAddress() function would gets the IEEE 802.15.4 Extended Address. It could be that you are not setting the extended address persistent, so it is changed upon reset/flash.

Regards,
Amanda H.