ePMP lan not work

On the two devices LAN not work but AUX (ether2) work OK (shows connection). Can be used  AUX as an LAN?

On newer firmware you should be good. (>2.3 IIRC)  Be aware however that future firmware versions may (hopefully) offer more control over the two ports (separate routing, firewalling, etc) and it's possible once disabling/enabling the second port is exposed in the webUI that it will default to disabled.