Need help with DSL-AC68U with Merlin Issues

[Melvin]

Summary, from a site : http://whatsyourrouter.com/mybb/showthread.php?tid=86&page=1

i flashed DSL-AC68U with Merlin. I dont need the DSL feature, all i need is to configure VLAN for LAN Ports.

I selected Dual-Wan, Primary, Ethernet Wan, Lan Port 1 and Secondary, Wan.

I encountered issues and i need help/workaround to these behaviors

1. ISP Profile under IPTV if selected for (Malaysia-Unifi-Home) to internet Vlan 500 and vlan 600 for IPTV (Lan Port 4). Only lan port 4 vlan is changed to 600, lan port 1 vlan remains at vlan 3. Lan port 1 is selected as Wan Ethernet port.
2. Under Internet Settings, 801.q is selectable, after saving, remains unselect. Vlan ports and etc remains blank no matter what information i selected or keyed in.
3. Unable to flash back to official firmware through recovery utility tool it says router not in recovery mode.

Things i tried

1. Robocfg to set vlan. Robocfg shows the changes, UI shows the changes, after restart modem, settings reverted back to Lan port1 vlan 3.
2. User Script, very new to this and not sure what i am doing. Tried to set the vlan with

   robocfg vlan 500 ports "1 5t"

   in a file without extension init-start @ /jffs/scripts. Erm.. how does user scripts works exactly?

Any workaround or guides on how can i set Vlan 500 for Lan port 1 via Primary Ethernet Wan?