Here is a small 512k Trapdoor Ram for Amiga 500:
Using the switch, you can disable the extra RAM or, if you have a rev6 or newer motherobard, use it as +512k Chip RAM (1MB in total) by applying this hack:
Board should be placed like this:
Board design is tested and verified using extensive memory tests and an extension ribbon cable to get board outside of Amiga's Case:
Note that AmigaKit's Trapdoor Ram board can't boot Amiga using the cable extender i use to test memory externally, prooving the superior stability and reliability of board's design.:
Anyone interested, please contact at: ikonsgr745@hotmail.com