OpenWrt 19.07.10. Missing eth1 on Mikrotik hap mini RB931-2nD. How to move one port from Eth0 to Eth1?

I've just installed the last available firmware OpenWrt 19.07.10 r11427-9ce6aa9d8d on my Mikrotik hap mini.

In Network\Interfaces system tells me that WAN interface has error: Network device is not present.

If I go to WAN->Edit->Physical settings and switch from Eth1 to Eth0 (and also remove Eth0 from my lan), then WAN turns on and works fine. But I have no ethernet ports in lan therefore.

How can I extract 1 ethernet port from a device called Eth0 and move it to Eth1?

is this your device?

The device is old and only has 32MB RAM. You wont get far with it. Sometimes its just time to move on. Do yourself a favor and put it into recycling. Its not a good idea to attach that to the internet with a collection of 4 year old unpatches security issues.

If you still don't want to give up, I would first check the log file, if anything points to memory issues. If you are out of mem, redirecting more ports to WAN won't solve it.

Hi. Yes, this is my model.

By your description, eth0 is a switch. You cannot "move" the port to eth1 - as it is a single Ethernet port.

it is not necessary to dispose of this device.
The manufacturer has a very good firmware with just as many options as OpenWRT.
This device is “End of Live” but there will still be updates and security fixes for the next few years.
The mountain of garbage is already big enough.
Mikrotik has the most options from the manufacturers, it is most unnecessary to use Openwrt with Mikrotik.