That is neat!
I think with the FDHD upgrade, all one did was replace the four ROM chips and the IWM, so with the ROM SIMM containing a later, FDHD-supporting ROM, simply replacing the IWM with a SWIM chip should be enough.
And it's kind of odd that the supposedly universal IIsi ROM doesn't work. Do you have a full MMU chip installed? Maybe the architecture is too different (being a 68020, with every subsequent machine being an '030).
I wonder if this would work on a IIx? }
c
I think with the FDHD upgrade, all one did was replace the four ROM chips and the IWM, so with the ROM SIMM containing a later, FDHD-supporting ROM, simply replacing the IWM with a SWIM chip should be enough.
And it's kind of odd that the supposedly universal IIsi ROM doesn't work. Do you have a full MMU chip installed? Maybe the architecture is too different (being a 68020, with every subsequent machine being an '030).
I wonder if this would work on a IIx? }
c