I know firefox OS is only on the roadmap, and is not fully supported yet… Just one annoying bug really, besides this firefox OS works like a charm for my specific project 
When building for firefox OS, the following luanch_path is defined in the manifest.webapp:
"launch_path": "\\index.html",
Just changing this to:
"launch_path": "/index.html",
Fixes the problem for not being able to run the app…
Could this be changed in the build? It’s pretty annoying to change this everytime I build the app 