DD-WRT on Netgear WNDR3400 - Bugs and Workarounds

Not sure if these are DD-WRT bugs, or WNDR3400 specific, but here are some bugs I ran into and worked around... 

1) Dynamic DNS does not update
As far as I know this is a DD-WRT bug, not model-exclusive. My workaround is to simply sign up for dnsomatic.com. Once you configure your DNS hosts, here is the workaround:

Add to Firewall Startup

wget https://yourusername:yourpassword@updates.dnsomatic.com/nic/update -O /tmp/var/dnsomatic.log

2) When specifying custom DNS (such as Google DNS or OpenDNS), and using PPPoE, the third DNS is always populated by PPPoE provided DNS, and seems to have priority over the custom DNS

Discovered this when I was getting Verizon's hijack page instead of OpenDNS's. Here is a workaround to overwrite the DNS set up by DD-WRT with PPPoE with your custom DNS..

Add to Firewall Startup

nvram get wan_dns | awk 'BEGIN{FS=" "}{for (i=1; i<=NF; i++) printf "nameserver %s\n", $i; }' > /tmp/resolv.dnsmasq
killall dnsmasq
dnsmasq --conf-file=/tmp/dnsmasq.conf

You can use both workarounds simultaneously.