CyberGraphX supported the GVP EGS Spectrum. The Retina Z2 had an EGS
emulation mode didn't it? I think I remember reading about that in the
original documentation for my card when I got it. A card I still have
to this day though I haven't had an Amiga to put it in for at least 5
years. :(.
What I'm thinking is, that the CyberGraphX team must have tried to get
the Retina Z2 to work by emulating CGFX in the Retina Z2's EGS
emulation mode. RobR always told me that the reason why the CGFX team
never released the Retina Z2 drivers is because they never could make
them fast enough for effective gaming compared to the rest of the
videocards, so they scrapped the drivers. I tried to convince him
that there would be enough people who just wanted the screenmodes for
general purpose computing(Web browsing, a higher resolution workbench,
etc...) to release them, but they wouldn't do it anyway.
I believe that if someone could create a CGFX to EGS conversion
process then parlay that to the Retina Z2's EGS emulation then you'd
have a decent facsimile of the orignal Retina Z2 CyberGFX drivers.