It's been a long time since I worked at Geoworks and my memory is a bit fuzzy. The tool chain was highly proprietary object oriented assembly. The builds were all distributed for speed. The tools were all developed on sun workstations. There was a strong pivot to tablets (inspired by apple newton) and smartphones by the time I joined. Eventually a toolchain around an object oriented extension to C was developed and I don't believe that required a sun workstation, but I don't remember the details.
I believe G offers a sort of interview workshop at some of their sites. Not sure what they are doing during the pandemic. A recruiter could tell you if they offer some sort of prep workshop.