Wan to Lan Bridge for Voip

Routers
1

Hi All,
I would like to use the ISP Modem/Router only for Voip and my GL-MT6000 Flint 2 for the rest (lan and wifi).
So I connected the Flint 2 Wan port to the ONT and configured ppoe connection, it works perfectly and i can surf the internet.
My ISP in Italy use two VLANS ID:
1035 for Voip
1036 for Data
Searching in the Net, I added Eth1 (i think is the fisical wan port) in br-lan bridge ports, i tried to create tree vlans (802.1q), accessing to Luci panel, with ID 1, 1035, 1036 (in interfaces > devices > add device configuration) without mac address (i don't know if is requested), then create same tree IDs in br-lan device activating bridge vlan filtering and tagging the wan port (it should be eth1) for ids 1035 and 1036, tagging the lan3 port (the lan port connected to the isp modem router) and untagging the other ports (lan1, lan2, lan4, lan5) for vlan ID 1.
But the Flint 2 does't save this configuration and activate the roll back automatic procedure.

So I realize that the eth1.1036 already exist but not as vlan 802.1q but as network device, may be I have to create only other two network devices (instead of vlans 802.1q) called eth1.1035 for voip and eth1.1?
Can you please explain me how to make this correctly? I’m new to the Openwrt world.
I installed Openwrt firmare ver. 24.10, but i cannot be able to configure wan, it connects (isp ip assigned) but cannot navigate the internet (maybe because i used vlan 802.1q instead of network device?), so i flashed back the firmware version 4.8.2 release 3.

Thanks, any any suggestion is appreciated

2

I had an issue with ‘roll back’ when modifying the bridge interface VLANs on version 4.7.x firmware because of the confusion with the VLAN Filtering checkbox. I haven’t tested it on 4.8.x yet so it still could be doing the same thing. So, you might be experiencing this same situation on 4.8.x.