This is an 802.11b version of Asus WL-500g. It has got the same board inside, only miniPCI wireless card is different.
|Version/Model||S/N||OpenWrt Version Supported||Model Specific Notes|
|v?||46IGE16103||Kamikaze 8.09.2 , Backfire 10.03.1|
|v1||upto 48IGE17770 (?)||Whiterussian 0.9||WiFi miniPCI Broadcom WL-120b (BCM4301)|
|v2||48IGE17771 and above||?||WiFi miniPCI Ralink WL-127 (Ralink RT2400)|
Wireless interface worked only in White Russian 0.9 and older for me (and only in AP mode or client mode with WEP encryption). If you want to use this device in client mode with WPA encryption, you may replace your wireless card with something better (WL-120g, Atheros CM9, etc.).
Reason for having root on external drive is that you want to install more packages than fit into 1.5mb of internal memory.
To check if root is mounted from external disk, check it for space: df -h /overlay or df -h /jffs. Do not install some of important usb packages like 'kmod-usb-core' when root is on external usb. That will probably disconnect the usb with root. So reboot without usb, install packages on internal root and copy updated root to usb root afterwards.