I just bought one of these and installed the latest Asus WRT Merlin firmware and noticed under tools in the webui it shows the WAN port as having VLAN2 tagged on it... as we all know it needs to be VLAN10 for Spark Fibre. So i began a long stint at googling and evetually came up with the following commands to change the VLAN in the NVRAM and make it persist after a re-boot. This is all done via SSH using Putty

nvram unset 'vlan2ports'
nvram unset 'vlan2hwname'
nvram set 'vlan10ports=0t 8u'
nvram set 'vlan10hwname=et0'
nvram commit