I would try the porridge again, but this time mix a fair amount of fruit in with it and make it with water instead of milk. It was always a huge hit with Alister. You could possibly try introducing some vegemite/promite toast fingers for him to suck on if he is able to sit up quite well in his highchair. Not every day, just every few days or so as something to break up the 'usual' breakfast for him kwim?