DD-WRT provides a lot of builds for different flash chip sizes. Sometimes though, you might need a module or two that isn’t included in the compiled firmware. Fortunately because of the way DD-WRT is developed (open source) you are able to grab the DD-WRT kernel sources from SVN and do a bit of DIY kernel module compiling. Though its not as simple as it sounds, but hopefully this general guide you get you on your way in compiling kernel modules. For this specific guide I am demonstrating how to compile IPv6 modules.