I finally received the dLAN 200 USB Extender from Develo (http://www.devolo.com/en/Downloads/dLAN-200-AV-USB-extender). It actually comes in pair, with one side having a USB host port and the other side having an Ethernet port. These 2 are linked together through Homeplug AV protocol, which means they simply ride on household electrical cabling for communication.
Following are the steps I have taken to upgrade this dLAN 200 to the open-source OpenWRT firmware. And with a USB-ethernet adaptor, I can conveniently have remote access to my home router via this dLAN 200.
Before we can upgrade to OpenWrt firmware, a transition firmware has to be installed. This transition firmware will make dLAN 200 to read OpenWrt firmware file via a USB stick and will perform the upgrade for us.
The transition firmware can be downloaded from here:
Extract, and follow the steps in readme.txt, which is to run usbextmassupload.exe and wait for 10-15 minutes till it is done.
The next step is to build OpenWrt firmware. The build steps are clearly described here:
However, for my build, I need to enable a few more configurations, including: kmod for my USB-ethernet adaptor (DM9601), iptables to configure netfilter, and udhcpc to obtain DHCP from my home router.
The complete build image and packages are available here:
We are going to use this file openwrt-mcs814x-dlan-usb-extender-upgrade-squashfs.bin from the build for upgrading the dLAN 200.
Prepare a USB flash disk, formatted to FAT32. The volume label should be AUTOUPDATE. Copy the file over to the USB stick and rename to autoupdate_image.
Plug the USB stick into dLAN200 and power cycle. It will start reading the file and perform upgrading. During the process, the power led will be blinking. It can take up to 10 minutes, and once it is done, the power led will stop blinking.
Reboot the dLAN200 and now it should be running OpenWRT firmware.
Now it will have static ip address of 192.168.1.1. Once configured by laptop IP to the same subnet, I can telnet to 192.168.1.1 as root (no password at the beginning).
Obtain IP address from the home router:
udhcpc -i eth1 -q echo "nameserver 18.104.22.168 > /etc/resolv.conf"
Enable internet sharing so I can connect to the internet via dLAN 200:
iptables -t nat -F iptables -t nat -A POSTROUTING -j MASQUERADE --out-interface eth1