S.F.
Being that he's 6 months, try mixing a bit of apple sauce into the cereal. The baby cereal tastes pretty bad, so perhaps he wants something different. Perhaps try other types of baby cereals, rice, oatmeal, mixed grain. My son like the oatmeal the best. There are multiple kinds of apple sauce on the market, mango applesauce and strawberry applesauce. My boys loves those.
Maybe try some veggies mixed into the cereal as well such as carrots, yams, etc.