If you have any low-memory OpenWRT device (4MB of flash) you will probably fill up any free space quickly after the initial OpenWRT install and need more room to grow. Luckily, you can transfer your root file system to a flash drive and boot off of it as long as your access point has a USB port.
If you are following along with our Western Digital N600, you probably don’t need to do this.
I was lucky enough to snag a Western Digital N600 router recently for $10 via Woot and have been working through the process of getting it configured with OpenWRT and cjdns.
For $10, I didn’t think I was getting a whole lot, but these devices sport a popular Atheros chipset and are perfectly compatible with OpenWRT’s latest version (Chaos Calmer 15.05 at the time of writing). For the uninitiated, OpenWRT is an alternative firmware for routers that allows for an advanced set of features and more customization.