Other folks will tell you to add sockets, or solder chips onto your motherboard, to fill up those blank spots you see now.
I've never heard anyone recommend doing it as nobody seems to have gotten 1mb chip on the motherboard and 0.5mb @ c00000 working. I had a 2mb megachip upgrade that left the trapdoor working though (IIRC it was the one fitted with 2mb so it didn't need to use the motherboard or trapdoor ram for chip ram at all).