Yeah, you need an old Linux version IIRC because it depends on a particular NFS version... I think it's important to get a feel for how the actual hardware felt, though.
It needs NFSv2 in the images as distributed on OpenGenera 2.0 distribution CDs - there exist patches for NFSv3, but there are also userland NFSv2 servers that can be used.
For integration of some of the network details, you need NIS (aka Yellow Pages).
The big issue is X11, because around X.Org R7 they have made changes that result in hangs of the Genera X11 client in certain conditions, including IIRC handling of modifier keys - and crucially it will hang on shutting down the machine (for example to save new image).
There are patches for everything other than NIS (and you can avoid using NIS), but you have to hunt for them. AFAIK they are included as part of Portable Genera.
It seems nfs-ganesha which used to have v2 support dropped it since then, but you might be able to compile 1.5.x release tree which is still on github.
As for patched systems, I know I have seen places which had patched images to load from, but there's non-trivial chance that they are slightly bitrotted.
