On the combination ROM/Cache module I presume that the majority of pins are active. On the Cache Only module, I presume that fewer pins are active.
Agreed.
If you can identify which pins are for the ROM function, you can disable them. That would leave you with a ROM/Cache module on which the ROM is disabled and the Cache is active.
Unfortunately the PCB is multilayered so I can't follow all of the traces from the pins. It might actually be easiest to desolder the ROM than try to disable the ROM pins. I just hope that there isn't anything I would be overlooking if I did that. There do
seem to be a lot of 'dead end' traces on the ROM-only module so I hope that the machine will just ignore the lack of ROM on my 'frankenmodule' like it overlooks the lack of cache on the ROM-only module.
Are the pinouts in a developer note somewhere?
That is a very good question and the answer would be incredibly helpful. Does anyone know where I might find this? I have some old Apple developer docs that I can search through and see if I can find something useful.
