I upgraded my HD10-250 by purchasing a 500GB Seagate drive, and then I imaged it using Instant Cake. It booted up correctly, and I got networking going, and configured it to use the network to communicate, then then it downloaded the 6.3a software from DirecTV. I then used Slicer to install the 6.3a software. During the 6.3a upgrade process, I switched it to a static IP address, but when I entered the address, I made a typo with the address. The upgrade process told me to edit the rc.sysinit.author file in order to correct the IP address error. I have done that, but the system doesn't seem to recognize the Ethernet interface. The machine cannot speak to the network, and the other devices on the network cannot see the machine (it's not pingable). With the exception of networking, all other aspects of the machine appear to be working correctly. My network interface is a Netgear FA120.
It's been many years since I worked at Unix command prompt, so I am not a complete Unix novice. On the other hand I certainly am not a Unix expert, and I've never worked with Linix (only used HP-UX and BSD). I'm hoping I can provide someone here some of my configuration files, and perhaps we can figure out what is mis-configured so that I can get networking up and running so I may add more features to my system.