fallbackRoute when error on start of app (deep linking)

How do I set a fallback route for when there is an error loaded the page and there is no previous location set in the router?

I get the following error and want to handle it gracefully.

“Router navigation failed, and no previous location or fallbackRoute could be restored.”

Question, is there a method similar to the mapUnkownRoutes() to handle these cases? I.e. mapFallbackRoute()??