OK, so, bottom line do *not* try to `dd` my way to a painless backup/restore, yes? (RT-AX92U)
Personally I don't see any reason not to use the GUI save/restore feature. It's designed exactly for the situation you're describing.
I did see several backup utilities over in the Merlin forums, but a) I don't have it and b) I don't think it's supported on the AX92U. GUI backup is a thing but I reflexively avoid it, probably because everybody on here complains about "dirty upgrades" and how restoring settings from a previous firmware version brings the devil in to the house or something. If I had a complete understanding of nvram variables, maybe I could selectively restore them (via `nvram set`) by hand....
I forgot you weren't using Merlin so that's even more reason to just use the GUI options because you won't have a complicated setup involving user scripts.
The "dirty upgrade" just refers to updating the firmware version without following it with a factory reset and manual setup. In other words a "normal update" that 99.9% of users would/should be doing (especially when using stock firmware). The problems only come when trying to reload settings taken from a
different version of the firmware, but that's not what you're doing (AFAICT).
Side note: Like
@toaruScar in post #10 I also have an automatic process (automatic because I'm running Merlin) that performs an
nvram show
every time the router boots up and stores the output in a timestamped file. So if I make any changes it's easy to
diff
the most recent file with an older one to determine what has changed (assuming a reboot has happened since the change). Sometimes it's easier/quicker to just identify a rogue variable this way and correct it rather than having to go through the "restore settings" procedure.