I've been working on this for a while and found through trial and error that there are a lot of problems with this motherboard that manifest several issues that affect the ability to run Windows 98 acceptably.

ACPI support is completely broken and hangs the system during installation every time; the only way to install Windows 98 is in APM mode. The IRQ Tables provided by the BIOS have errors, causing IRQ steering for PCI devices to be broken, requiring each "important" PCI device to have a unique IRQ for the system to function.

I need the following devices at a minimum to have their own private IRQ:

* Video
* Sound
* USB (for mouse/keyboard)

Although PCI devices cannot have their IRQs assigned explicitly, they can be manipulated by enabling and disabling different devices in the BIOS. I found that it was possible to get a working system with the previously mentioned devices this way. However, this list does not include a Disk Controller, which means that DMA is missing, and this makes the system very unresponsive when heavy disk operations occur, as well as a degraded overall experience.

Why can't this be solved? I have come to the realization that, despite lots of other IRQs being available, the BIOS will always assign all four of these devices to IRQs 7, 10, and 11 only. The problem here is, specifically, that I want four devices to have a unique interrupt, but there are only ever 3 IRQs available to me. However, I do have a clever workaround.

While examining IRQs on the disk controllers, I found that one of them was always assigned IRQ 14, but that there was never any device attached to it on any of the onboard SATA ports. I have also discovered unpopulated pads for an IDE pin header on the motherboard. I think that if I solder a header onto it, that I will have a working disk on its own IRQ, giving me the 4 unique IRQs for a pleasant Windows 98 experience.

Will this idea work? I have no idea. But I'm crazy enough to try it and find out!

I added a header for the onboard IDE controller, and it worked. However, it's not bootable and is only detected from within Windows. I thought that even if it wasn't bootable, I could still bootstrap it from GRUB4DOS, but both it and FreeDOS fail to detect the drive controller.

I wanted to boot Windows 98 from this IDE controller so that I could enable DMA on an IRA that didn't conflict with other devices. But since it's not bootable, then this project to get Windows 98 running on this system is a failure.

I found some information about the IDE drive controller here:

https://linux-hardware.org/index.php?id=pci:1 … -03ec-1019-2609

Here are some photos of the header attachment process, for your enjoyment.