Preheat oven to 375. Prepare 16 mini loaf pans with cooking spray and flour; set aside. Add flour, sugars, oil, and two teaspoons cinnamon in a mixing bowl. Rub with fingers until blended and texture is crumbly. Reserve 2/3 cup mixture; set aside. Add remaining cinnamon, granola, walnuts, baking powder, baking soda, and salt to remaining flour mixture. In a small bowl, beat eggs into buttermilk. Add to flour mixture. Fold in blueberries. Mix until all is moistened. Spoon three ounces or half cup batter evenly into prepared pans. Sprinkle each loaf with reserved crumb mixture, pressing gently to stick. Bake for 20 minutes, or until lightly browned on top.