Honestly, it's normal. Not all babies sleep 12 hours by 6 months old. There is a lot going on during that first year. LOTS of growth, lots of learning, lots of discovery. This all can translate into a HUNGRY, CURIOUS baby who is still trying to figure out his/her rhythm.
Trust me... I know what it feels like to not sleep. My daughter was 13 months old before she slept 12 hours straight. That first summer was horrible because she went through a growth spurt and wanted to PLAY at 3am!
Keep doing what you're doing. Make sure he is dry and has a full tummy. I'm not a fan of the cereal in the bottle thing... choking hazard. But, a little cereal before bed isn't a bad idea. Keep in mind, he may also just need that reassurance that you are there. And that's OK! :-)
When my daughter was a year old and I really felt that her night waking was more of a habit and she didn't NEED anything (she didn't nurse vigorously like she was hungry etc...) then I would get up with her, quietly tell her it was not time for milk, rock for a minute or so and then put her back in bed. I always offered comfort. It didn't take more then a week before she was sleeping 12 hours straight.
But again, I only did this when I was certain she was not waking up because she was hungry and she was old enough to know Mama and Papa were always there.
It's hard. I know it's hard. But, it is part of the package. It does pass... and now there are times when I do miss those middle of the night quiet moments alone with my daughter. She is on the go now.... rarely lets me cuddle her. Those were very special moments in the dark... all snugly together. I will never forget them.