Received ZTE H267A today. What I did after the installer completed the installation.

At Internet > WAN > DSL tab > DSL Connection
1. Create new item (Internet bridge VLAN)
- Connection name: BR_VLAN_500
- DSL Transfer mode: PTM
- VLAN: On
- VLAN ID: 500
- Apply

2. PPPoE set to Off

3. Click VLAN Trunk tab
- LAN1 set to On
- Supported VLAN number: 1
- VLAN ID1: 500
- PVID: N/A
- Apply

4. Once done connect own router WAN port to ZTE LAN1. HyppTV connect to ZTE default LAN4

Optional>>
5. If you want to pass the HyppTV to own router then
- At DSL connection > BR_VLAN_600 set to On (default is On)

6. At VLAN Trunk
- LAN1 set to On
- Supported VLAN number: 2
- VLAN ID1: 500
- VLAN ID2: 600
- PVID: N/A
- Apply

2 minor observations. I will try to fix it when have time.
1. ZTE system time not sync with time server. Suspect it can't pick-up internet traffic
2. Internet LED is off. Should be related to above

0. Have you rechecked all the steps I stated? Standard question 

1. What's the WAN (internet) settings in e4200 dd-wrt?

2. You need to configure PPPoE in dd-wrt with UniFI login details (btw I do not have dd-wrt but setting should be more or less the same)
- Connection type = PPPoE
- User name = xxxx@unifi (you unifi login)
- Password = xxxxx (you need to check from UniFi installation sheet or ask TM 100)
- Connection mode = always on / keep alive
- keep the rest default

3. My instruction was based on assumption that the user knows how to configure own router