In the open source firmware world, OpenWRT is well known for its expandability, stability, and long list of standard and additional features.  One can also enhance an OpenWRT install by way of installing additional packages to suit multiple usecases.  So, it's easy to see why advanced users looking to get more from their router would want to use OpenWRT - I'm going to show you how to get this version on your WNR3500L.

Step 1: Prepare Your Router

To start, download this release from the OpenWRT for WNR3500L download section.

Then, you'll want to perform a 30-30-30 reset using the steps in this guide, as you should always do before installing any new firmware.

Step 2: Reflash with OpenWRT

The next step depends on which firmware version you have installed.  If you're coming from the NETGEAR original firmware, you should be able to upgrade with the CHK file through the web interface.  

If you are on existing DD-WRT installation, you will want to use telnet and TFTP as shown in this tutorial.

Step 3: Exploring OpenWRT

Once the firmware has been installed, perform a reboot and head over to 192.168.1.1.  If all proceeded smoothly, you should be presented with a dialog box allowing you to change the OpenWRT default password.

Here, you can see this new version of OpenWRT running on the WNR3500L.  Let's take a quick tour.

OpenWRT has fully-featured monitoring and log applications built-in, such as CPU usage and bandwidth monitoring.

Here's the device status screen, showing RAM usage and other stats.

This build of OpenWRT for the WNR3500L is known for supporting almost all current wireless security options, most notably WPA for Personal (WPA for Enterprise is not supported as of this release.)

Step 4: Continue Exploring and Testing

As with all new builds, this version of OpenWRT is "beta" and may not support all features.  Continue forward with your testing and let us know what works well, what can be updated, and your general experiences with this brand new build.