1mb rom maprom possible ?

[Piru]

Blizzard maprom only does 512KB, indeed.

[Piru]

@-D-

So the only option would be Blizkick using the "extresbuf" feature, correct?

Well, the extra romtags could be put to extresbuf, sure. Not directly as a 2nd ROM though (the modules need to be relocatable).

[Piru]

@countzero

what are my chances of removing the 27c256 on the MKIV, reading the firmware, making necessary changes for 1mb maprom feature and burning it into a new rom ? (hmmm 0 ? 0.5% ?)

The actual MAPROM feature is some HW magic that is triggered by the software. I doubt it's expandable without some rather complex hw modifications (more complex than reflashing the EPROM).

Anyhow, the MKIV ROM can be read quite easily (just save it to a file). It won't help much in this case, however.