ASUS routers MAC addresses discrepancies

FreshTomato Firmware 2021.8 K26ARM USB VPN-64K

ASUS RT-AC1900P, ASUS RT-AC56U and many others.
Used / Total NVRAM 35.88 KB / 64.00 KB (56.07%)

This particular issue goes back to original Shibby firmware releases. It exist at least in versions 110 - 132 and has been carried over to FreshTomato as well.

In “Advanced”, “MAC Address” there is a list of various MAC addresses for WAN, LAN, WL0 and WL1.

After NVRAM reset Firmware always correctly reads the LAN MAC address of the router. But WAN MAC address sometimes being read incorrectly, see attached screenshot #1. If you click “Default” it would sometimes read the WAN MAC properly, see 2nd screenshot. But if you click on “Save” it will confirm the changes, warn you that WAN IP will change, etc. But the WAN MAC address won’t actually get changed., it will stay the same as it was originally. On some routers it works properly and on some it doesn’t. After spending some time I think I found a culprit. FreshTomato reads MAC address incorrectly only if the last 2 digits of the LAN MAC Address are E8, so WAN MAC suppose to be :E9 but it reads it incorrectly as :F8 instead. Label on the router box clearly states :E9 for WAN and as a test I installed DD-WRT and sure enough it read it properly, see screenshot #3. Attached screenshots are from RT-AC1900P but I have exact same issue with RT-AC56U and RT-N66U as well. Needless to say that proper WAN MAC address is important when it comes to avoiding duplicate MACs on the ISP side and getting proper IP address as well.

Another more minor issue is with default MAC address for WL1. Firmware also reads it incorrectly and when you click on “Default” it reads last 2 digits properly but changes 1st 2 digits to incorrect value, see screenshots. Unlike with WAN MAC address when you “Save” changes for WL1 are being retained.

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