Glad its working now but just a question? Did you try to use the usb and change it thru the info tab? Something rings a bell that I had to do that once but might have been because we forgot the ip address so didn't know what to set the laptop to in order to connect. I've been able to change the ip address to what I want thru there and then get to it by the ethernet.
If you've set and forgotten an IP address, I believe the IPConfig utility in Launchpad can still set the IP via the MAC address (printed on the POM PCB or the serial number for Ethernet Do-Mores)
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Another trick that sometimes works with a port that has a fixed but unknown IP is to hook up to it, start Wireshark, and the port is often ARPing around announcing its IP address.
Or you can use the magic handshake to wipe the IP config and start over.