So, you're removing the layer=true parameter? Does that mean that now LibraryServlet outputs the same wether you're using a layer or not? I don't think that will work because either you're outputting a define for sbt/_config in all cases, and then it won't work for dojo 1.4.3 because it doesn't support plugins, or you'r outputting a define for sbt/config in all cases, and then it won't work when using a layer because the layer already contains sbt/config and then it will throw an error when trying to define sbt/config again (and the sbt/config on the layer contains no configuration)