Board Thread:TV Show Discussion/@comment-4708902-20160719222748/@comment-25371179-20160720035738

I think his point is that it has not been made explicitly clear in show canon that bastards have sigils that are the reverse colors of their family sigil. It may be this way in the books, but that doesn't mean it's the same in the show. So before we jump the gun and update Jon's article with a white wolf sigil, it would first have to appear in the show, and be made clear that Jon Snow is actually using it.