Preheat your waffle iron. Mix the buttermilk with oats and let stand for about 15 minutes.
Whisk the flours, wheat germ or cornmeal, baking powder, baking soda, salt, and cinnamon in a large bowl. Stir the eggs, oil, honey, mashed banana, and vanilla into the buttermilk/oat mixture. Add the wet mixture to the dry mixture, and mix just until everything is moistened.
Use approximately 2/3 cup batter to cover an 8-by-8-inch waffle iron. (Tip for larger waffle irons: Use 1/3 cup per square.) Cook each waffle until the steaming slows down a lot--approximately 4-5 minutes for golden brown, crunchy waffles. Keep warm in the oven while you cook the rest.
