Recently I found an ImageWriter dump and also found a schematic. I've been looking for those for a long time.

One thing which puzzled me was exactly how the address decoding worked, so why not model it in Logisim?

It uses a 74155 piped into a 74156 and once modeled it gives the expected results:

Logisim is cool, I just learned how to do splitters.

[Linked Image from]

Modeling the 74155
[Linked Image from]