Orin Nano – How to Modify Default MAC Address from EEPROM

[yen_chou]

Hi,
Platform: Jetson Orin Nano
JetPack Version: 6.2

I’m trying to modify the default MAC address on our custom carrier board.

Before making any changes, I was able to read the MAC address correctly from the EEPROM, and it matched the actual hardware address.

So I attempted to modify the EEPROM at address 0x50, specifically bytes 68 to 73, to update the MAC address as below.

root@tegra-ubuntu:/home/ubuntu# hexdump -C /sys/devices/platform/bus@0/3160000.i2c/i2c-0/0-0050/eeprom
00000000  02 00 fe 00 00 00 00 00  00 00 00 ff 00 00 00 00  |................|
00000010  00 01 00 01 36 39 39 2d  31 33 37 36 37 2d 30 30  |....699-13767-00|
00000020  30 33 2d 33 30 31 20 41  2e 31 00 00 00 00 00 00  |03-301 A.1......|
00000030  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
00000040  b0 48 00 00 **66 55 44 33  22 11** 31 34 32 34 33 32  |.H..c,.-.H142432|
00000050  33 30 31 38 33 31 34 00  00 00 00 00 00 00 00 00  |3018314.........|
00000060  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
*
00000090  00 00 00 00 00 00 4e 56  43 42 00 ff 4d 31 00 00  |......NVCB..M1..|
000000a0  00 00 00 00 00 00 00 00  00 00 00 00 33 22 11 e1  |............3"..|
000000b0  03 00 01 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
000000c0  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
*
000000f0  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 ad  |................|

However, after rebooting the system, the MAC address did not change as expected.

I would like to ask:

1. Is it valid to change the MAC address by modifying the EEPROM directly?
2. What is the actual process or flow the system uses to retrieve the MAC address during boot?

Thanks in advance for your help!

[WayneWWW]

Orin Nano and NX ethernet MAC addr is not read from EEPROM but directly from the PHY.

Please contact Realtek for the tool to modify it.