Mix the wheat flour with the corn flour, oats, baking powder, salt and baking soda in a large bowl.
In another bowl, mix the buttermilk with the oil, sugar and eggs into a homogeneous mixture.
Then slowly, while stirring, pour the buttermilk mixture into the flour mixture. Make sure there are no lumps.
Heat the waffle iron and lightly brush the top and bottom with oil using the grease brush. Also prepare a baking tray so your waffles can cool down.
Divide the dough between the baking sheets and close the appliance.
Bake the waffles until golden brown (2:30 min at setting 5)