Hi all,

It's my first topic here, but I've been lurking for quite a while already, so the time has come to finally begin posting 😀

Gravis sound cards, and especially the InterWave based ones, are among the most interesting retro-hardware parts for me. I've been thinking what Gravis could do to even further improve its PnP design and have come to some possible ideas:
1. 72-pin RAM slot - we've already designed an adapter in order to cover this, you may check here if you want.
2. More embedded RAM - do you have any ideas about possible replacement for the embedded 512KiB 40-pin SOJ chip? GUS interprets the SOJ as 2 banks, meanwhile the InterWave chip is able to address 4MiB per bank, thus making it possible to replace the chip with 8MiB one (but I haven't found any proof that such chips were ever produced in SOJ40 package due to the increased density, I guess).
3. More embedded ROM - official InterWave datasheet claims support for up to 16MiB of ROM. A couple of starting points to discuss:
3.1. Is it possible to replace the embedded 1MiB ROM with a 4MiB ROM containing another GM-compatible wavetable (in the same 44-pin package - there are plenty of those present on different MIDI daughterboards, Roland SCB-55 and Diamond Monster MIDI, for instance)? I believe, a simple replacement won't be enough as the synthesizer chip will not be able to correctly work with the ROM image (even if it proves being able to address the chip correctly).
3.2. Is it possible to replace the embedded 1MiB ROM with a DIP42 ROM bit-by-bit flashed with the GSFULL4M file (official 4MiB GS soundbank included on the Gravis CD)? This approach seems much more feasible as I do not see any obvious obstacles for the synthesizer to use ROM-based image instead of a RAM-loaded one.

Any comments will be welcome!