Hello,
I upgraded my WRT1900ACs v1 from 19.07 to 21.02 RC2.
I wiped the 19.07 config as instructed and made a new config in 21.02.
I have been struggling for hours to figure out how to make ipv6 work again.
I finally found out that the MAC address of wan and lan interfaces were swapped between the 2 versions !
As I use the old 19.07 ipv6 link local ( derivated from MAC Address) to setup ipv6 PD to my lan, it was not working. When I discovered the change, it was easy to fix ipv6 PD.
Is this a bug, a normal behaviour due to DSA or my config wipe ?
How are generated the different MAC address ?
At least, I hope this could help others when they will upgrade .