Maybe someone can answer this for you ... I have a record on my laptop of all my router configurations and I cannot access either of the ones which I have changed the MAC which are in my camper. I am out of my camper in an apartment until the virus lets up. I don't use the Luci menus much these days because every since they started that "roll back" business, I get hit too many times with the roll back showing up when my Windows system is not responding fast enough. If you haven't tried it, check out WinSCP if you are a Windows person, just open the file tree like you were on Windows, open the config file with a Notepad like editor, save the file when you close it and either enter "reboot" in the top command window of the SCP screen or you can log into Luci and do the restart as well. (Did a search and some people were having an issue with this via the Luci menu back Aug '19 I believe but I didn't get too thick into their issue. Once you use WinSCP, you may see it as easier. They say not to change the control files directly because that Luci and their dotted.command line syntax handles all the changes associated, but this level of change will be fine if you reboot after editing the control file. Located in the WINSCP file treee at /etc/config/network, double click, the file opens, enter the edit, save and reboot the router.
From left to right on the MAC, copy your cell phone or laptop MAC exactly but the final 4 characters make up another number, using only digits 0-F. (0-9,A,B,C,D,E,F)
After you install WinSCP, set up a login entry:
Protocol: SCP Port: 22
Host name :192.168.1.1 (or your router IP)
User name: root Password: (router luci login password)
You'll get a big screen asking something about the login certificate not being valid and do you want to update it, say Yes.
There will be 2 boxes, the left will have your windows files and on the right there will be a /root/ with no files in that window but there will be a tiny icon with an UP arrow - double click that icon. Now a whole list of folders show up, starting with bin, dev, etc ,,,, and double click the "etc" folder to open it, then double click the "config" folder to open it, then double click the "network" file and you will get a notepad editing screen. Scroll down and add this line under the topic I named of "config interface 'wan'". Add anywhere under there and before you get to the next line starting with "config ..." Now after adding a blank line and inserting your change, close the Window with the X in the corner and select SAVE option. On the second line of icons next to "Synchronize" there is a tiny icon showing a black background with command arrow ">" where a tty terminal session is opened and you key in "reboot". Now close WinSCP and your changes will be saved. After giving the router time to reboot, you can log in and double check it was saved if you wish.
I just tried entering an "Override MAC" number on the WAN line of the Network, Interfaces, WAN, Edit, "advanced settings" where I entered the proposed new MAC address and saved the changes there and saved again on the Interfaces panel, then I used WinSCP to verify that the Network file had changed but it didn't - the router /etc/config/network file did NOT get updated. I am on release 19.07.3 which is one behind current, but I'm not sure if .4 out now fixes that or not. Safe bet to go with WinSCP if you can follow how to use it. Don't forget to reboot after editing the Network file by adding that new line with the MAC address in it. Also don't make any mistakes in the new MAC address you create, like misplaced colon or spacing out as double digits, or failing to use 0-F characters, etc.
