OpenWrt support for Linksys MX8500

[sppmaster]

@lytr

and not working (boot without cable connected):

Looks like a common issue to mine.
I currently have this issue on another product - Mikrotik RB5009UG particularly with kernel 6.6.
With kernel 6.1 everything was OK for me.
First I described what I found here.

@sppmaster

@robimarko, @Ansuel, @Borromini Don't you think below situation is a bug?
I think I have found what's going on even without a serial. But someone else will have to help with the solution if that is a bug.
Currently I only test this unit in my spare time and because of this I don't have the common usage environment as most of the other regular users.
If the unit is booted without any LAN cable plugged into any of the LAN ports and then later a cable is plugged into any of the LAN ports the connected device cannot get IP address and even setting manually IP, the router will still not be reachable and General failure error is printed during ping command.
The only proper way is to boot the OpenWrt with LAN cable plugged into any LAN port and then everything is OK.