Has anyone found a working workaround in the meantime
A 404 in the preview window is a result of a bug in the app being built (incl. code generated), not a bug with the Firebase Studio IDE itself.
One probability is that the Next.js router has not be configured for the route you are attempting to load. This can happen when mistakes are made in the code Gemini generates. To troubleshoot, ask Gemini something along these lines…
I'm experiencing a 404 when I view the current route. Perform a deep and thorough analysis of the Next.js router to see if you can figure out the problem. If you don't find the obvious problem, provide me with a comprehensive list of things to check so I can attempt to troubleshoot this issue. Include the common causes for seeing a 404 in a Next.js app.