I’ve been using dd-wrt on the same WNDR3300 for several years now, and have been through a wide range of firmware upgrades and downgrades. With the latest eko release, dd-wrt.v24-13577_NEWD_std-nokaid_nohotspot_nostor.bin, I have achieved secure 5GHz 802.11n + 2.4GHz 802.11g functionality that works with all 802.11n and 802.11g devices that I currently own.

To start, the WNDR3300 requires a firmware flash with a .chk file. The latest file available is dd-wrt.v24-12548_NEWD_mini_wndr3300.chk. Once the factory Netgear firmware has been flashed to dd-wrt, it can be reflashed with the standard dd-wrt .bin files.

After flashing to dd-wrt, you will have to perform a hard reset (30/30/30) as explained in the wiki at http://www.dd-wrt.com/wiki/index.php/Hard_reset_or_30/30/30. This step is very important to ensure your router runs stable.

After performing the hard reset, you can flash the latest firmware. I recommend dd-wrt.v24-13577_NEWD_std-nokaid_nohotspot_nostor.bin, as it is what I am currently using and have found to be stable. After flashing, perform another hard reset as explained in the wiki at http://www.dd-wrt.com/wiki/index.php/Hard_reset_or_30/30/30.

Once the router restarts, it will broadcast an unsecure 2.4GHz signal. You can connect wirelessly to begin configuration, and the router will assign an IP address via DHCP by default.

I generally leave basic configuration as-is, but I change the IP block from the default 192.168.1.x to 192.168.0.x to eliminate conflicts that are specific to my ISP. I use OpenDNS servers, so those are specified in the basic configuration but are not required. I set the time zone, and all other settings are left to the defaults.

I perform my wireless changes one at a time, and make sure everything is working before I make another change. This ensures that any problems can quickly be resolved rather than going back and trying to figure out where the problems are.

Advanced wireless settings are left to the defaults on both radios.