Just to confirm,  Ethernet Backhaul is working properly with Easymesh on the RE315 range extender running RE315(US)_V1.6_1.0.30 Build 230919 firmware.  Paired up to main router with no issue, however keep in mind these older models are limited to a 100 Mbps ethernet port.  

However it does work as advertised now.

Thank you for adding this support.