@Matt64. For all recent versions of AiMesh - when you tried to access a node thru the webui, you were redirected to the Router. So that's not new. To update the node's firmware, you can do it through the Router'sFirmware Upgrade for the selected node. Or you can do it directly via this url: (replacing xx.xx.xx.xx with the node's IP)
http://xx.xx.xx.xx/AiMesh_Node_FirmwareUpgrade.asp
There's nothing on a Mesh node you can individually configure. It is all propagated from the router. Yeah, that sucks. But I guess it keeps idiots from screwing-up their network.
Note: since you have different hardware types for your router and node, be very careful to flash the correct file for each model.