Options for additional chipRAM on rev8a.1 motherboard with 512Kb chipRAM on board

[Sim085]

f I upgrade a rev8a.1 motherboard Agnus to 2Mb version is it possible to add 1.5Mb of additional chipRAM through the bottom expansion board (I.e. without soldering additional RAM chips on the motherboard). I would like to upgrade the mother oard to 2Mb of chipRAM with little to no modifications to the motherboard itself. But do not know what is possible through the bottom expansion board.

[AmigaHope]

It's absolutely possible but would still require at minimum cutting/bridging some of the address lines -- the default faux-A500 versions of the rev 8 are jumpered to behave like an old A500, and you still might be stuck with 1.5M chip without further modification.

You're much, much better off just modding it to A500+ configuration. Soldering in some sockets is not difficult.

If you want to keep your neutered rev 8 A500 in pristine state for collector reasons (since they are so rare vs. the 500+), you're better off not making any changes to it at all and just letting it remain as an A500, and use a more commonly available Amiga as your daily driver.