I just did some work on the machine 2 tonight and give OMF a try and it was working both in sb16 and gus classic mode! I think I understand why: I loaded EMS. I never have the reflex to load emm386 when I want to play a video game.

I'm not so sure about how to load EMS in freedos but I'll seek in that way to make the game sound work on it.

For EMS in FreeDOS, don't use the included EMM386 version. Get JEMM386 and JEMMEX (for use with UMBPCI). JEMM386 is essentially a drop in for EMM386 (with reduced memory footprint), except it does have compatibility issues with some TSRs like softmpu. I haven't tried aweutil or sbpci drivers, but they could have problems as well.

Yes that's what I intend to try next. If my memory is good, I once try to use the emm386.exe that came with the ultrasound in an effort to test mega-em, but I dont remember clearly... I think maybe the odd version of emm386 that ship with megaem might be faulty.

From what I've read on the freedos website (http://help.fdos.org/en/hhstndrd/base/jemmex.htm) JEMMEX have it's own XMM. I think I might add 2 new option un my fdconfig.sys menu for JEMMEX and JEMM386. There is plenty of well documented options to play with too, they even explain why you might want to switch NOEMS on JEMM386 🙄 guess that's how you get XMS and something like 780kb of base...

I'm eager to give it a try tonight, I'll post my results here.

JEMMEX is intended to work with UMBPCI, so it lets UMBPCI handle UMB management. It doesn't manage XMM at all, just EMS. JEMM386 manages UMB in addition to EMS, the same as EMM386.

I did many testing with jemmex, jemm386 and himemx with no results at all. With jemmex only I get a strange error message from omf209

For some reasons I had to go and change "PNP/PCI CONFIGURATION" in the bios and think there is maybe something here. I'll have to refresh my memory about "PNP OS Installed: yes/no", "Resources Controlled By: auto/manual" and "IRQ Sequence: "15,11,10,9,12,14,5,7,3,4", "9,10,11,5,7,4,3,12,15,14"".

do you think it worth anything to force the guspnp to a certain irq config and assign them to "legacy ISA" on the bios instead of "PCI/ISA PnP" ?

Funny thing when I did use jemmex.exe (and no himemx) OMF2097 did an audio click on startup and bring an odd error message on the screen. Unfortunately each characters where corrupted and I could not read them, they look like chars from copy protection of space quest 4. -- couldnt reproduce ...

about jemmex, I am thinking it dont need himemx as I've tested it and I got the idea reading this page http://help.fdos.org/en/hhstndrd/base/jemmex.htm
it is sayd:

JEMMEX is an Expanded Memory Manager which has an XMM already included.

and

JEMMEX most likely is the better choice than HIMEMX / JEMM386 because
it will need less DOS memory than an external XMM + JEMM386.

I did try to load JEMMEX and HIMEMX and it beep and complain that "Error: XMM already installed" then you got xms only. I did try JEMMEX NOEMS, you get many XMS ram and 751kb of base! ... but no sound in OMF2097 🙁

Everytime I run playmidi.exe and play a midi from ultrasnd to make sure the card work. I start to think that freedos is the problem here, what do you think gdjacobs ?

I could try to remove the 10/100 nic and the usb card and change the matrox g200 for something more standard. I think this would be the next step.

YES ! Got it working ! With iweeprom 1.3 I've disable the sb emulation and gave two irq to the gus pnp. Then here is what I think made the trick, I ran prepgame in the omf directory, to program seem to have done some magic and now it's working. As the configuration file is not clear text I have no idea what prepgame did, I think I'll read more about that proggy.