The Amiga 500 series had a RAM expansion card that would plug into the trapdoor slot on the bottom of the computer. This would add 512k of fake fast RAM that was as slow as chip RAM. With some modification the FAT AGNUS could address 1 meg of chip RAM but to get it to work you would need to replace the Denise chip with a Super Denise. Kickstart 2.04 will recognize the added chip RAM. Kickstart 1.3 or older will not.
If you're not familiar with CHIP memory as opposed to FAST memory: CHIP memory is a combination of VIDEO and AUDIO memory that gets used as main memory if you run out of FAST memory. Fast memory is only accessible by the main processor so the processor never has to wait for its turn to access memory hence the name FAST memory.
