I've been working on getting OpenWrt up and running on my DGND3700.

I've been using Barrier Breaker r38302 and can get it up and running, usual
limitations obviously with ADSL, 802.11n and 5GHz.

this post explains how to get the 4 LAN ports to work but they do not work
as expected. That configures it so that in the switch config that port 5 is all the lan
ports and VLAN does not work to associate 1 port as WAN.

With a little bit of hacking around the kernel I have managed to get each port to
work on their own, but they are unusable past plugging it in. The port aside from
being on does not do anything further. The WAN port when set in a VLAN is not
able to get a DHCP lease, and the LAN ports do not issue leases.

[   13.420000] bcm63xx_enetsw bcm63xx_enetsw.0: link UP on WAN1, 100Mbps, full-duplex
[   13.428000] bcm63xx_enetsw bcm63xx_enetsw.0: link UP on port2, 1000Mbps, full-duplex
[   14.940000] bcm63xx_enetsw bcm63xx_enetsw.0: link UP on WAN1, 100Mbps, full-duplex
[   14.948000] bcm63xx_enetsw bcm63xx_enetsw.0: link UP on port2, 1000Mbps, full-duplex

shows over the serial port when plugging and unplugging (or in this case restarting the interfaces)
I have no idea what to try next to make them do anything other than negotiate the connection.

I want to test your updated firmware on my DGND3700. Could you please share with me your updated firmware, thanks.

I can share my firmware but first I should mention that there are the following limitations at present.

• Installation can only be done with access to serial console

• Device only works as a glorified switch due to no working WAN port or VLANs

• Sysupgrade does not work so future firmwares must also be installed by serial console

• BCM43222 wireless driver only supports 2.4GHz b/g so no 5GHz and no a/n

• No DSL modem support

The following few things are known to work though

• USB support on both ports

• LEDs

• Ethernet LAN ports

• WLAN, WPS and reset buttons (only reset button is configured with an action)

There may be a few other things that are working, or not working that I have not looked at.