citronalco wrote on 2022-03-20, 14:58:

I have a similar problem with that board.
Do you still remember what kind of hack you did? Or: Could you upload your modded BIOS here?

Please wait a few days.
User mkarcher is breeding something on that BIOS now.
+++ BREAKING NEWS +++
Just a few minutes he got the initialisation of a Matrox G450 with DVI output to work.
This card uses an PCI to AGP bridge. He has reported that there were bugs in the BIOS in the beginning of the POST that prevented the initialisation of a PCI bridge at the time when the graphics ressources are assigned.

So in my setup I replace the PCI ET6000 with VGA output by a PCI Matrox Millenium G450 with DVI output. Yihaaa!

Well, it did run fine with 33 MHz FSB.
But the G450 did NOT boot at 40 MHz FSB.
The reason was that the early BIOS code has divided the PCI clock to 20 MHz, but the Matrox did not like such a low PCI clock.

Disruptor wrote on 2022-03-20, 22:34:

Well, it did run fine with 33 MHz FSB.
But the G450 did NOT boot at 40 MHz FSB.
The reason was that the early BIOS code has divided the PCI clock to 20 MHz, but the Matrox did not like such a low PCI clock.

That's not something you can't fix using a BIOS patch, so here we go: Matrox G450 (with DVI outout) working on a HOT433 main board (UMC 8881)

I am not at all surprised by all the problems you've encountered with the HOT-433 board. The IDE/HDD stalling during Windows 2000 bootup was a problem I ran into some ago as well. Running your IDE controller on IRQ 12 resolved this issue? Curious. You mentioned later that the issue was further resolved with a BIOS hack to fix the IRQ routing table. Did you use Awdbedit? If so, what was the routing table before and after the hack?

You mentioned this BIOS hack a few times in the thread, but I could not locate your BIOS file uploaded to the thread. Did I miss it? Does your BIOS hack implement mkarcher's hack for getting the Matrox G450 working? Was the PS/2 mod added to the BIOS hack as well?

If you are looking for DVI on a PCI card that works on a 486, you may want to consider using the Matrox G200 with the MDR-20 flat panel add-on connector. You can then use a MDR-20 to DVI cable adaptor. This is what I've done on my IBM 5x86c-133/2x system.

Did you try EDO memory? I recall being surprised that this board works with EDO.

I see you've added USB to your 486. Check your Windows benchmarks with and without the USB card installed. When I ran these tests, I got a lower CPUMark32 score with the USB 1.1 card installed. I think the performance drop was in the 5-20% range.

Nice to see you got the PS/2 mouse working on the HOT-433 v1-3. This was on my ever growing list of things to figure out. Has there been any work getting the PS/2 mouse header working on the HOT-433 v4?

I don't have a HOT 433 v4 as my goal was to have a 486 mainboard with 1 meg of cache and PS/2 mouse.
The desire for a DVI output came later.

As I have 2 sticks with 128 MB of FPM DRAM I don't use EDOs. I don't remember whether I did tests with EDOs on this particular mainboard.

This board came with an AMI BIOS, but we've installed an Award instead.
He first fixed the IRQ routing table; that solved the problem with the IRQ 12 issue.
mkarcher had focussed on the PS/2 mouse next.

You find a BIOS here:
Success: Adding a PS/2 mouse port to the Shuttle HOT433 (using a dedicated keyboard controller chip)

I use a HighPoint IDE controller. It refuses to run at 20 MHz PCI clock. The problem with this board was that there were problems with early PCI autoconfig, so it refused to work on 40 MHz - that was divided to 20 MHz in early PCI initialisation. Now I test the board with 33 MHz, but the goal is 40 MHz FSB + PCI clock.
It seeems the GeForce 5200 PCI and Radeon 9250 PCI refuse to work; the Matrox G450 PCI works stable after adding a heatsink to the PCI-to-AGP bridge chip. Currently we're testing without the USB 2.0 card.

Thanks for your reply. It was not clear to me from the PS/2-HOT433 thread that mkarcher fixed the IRQ routing table in his BIOS patch of 2A4X5H21. I could not locate any mention of it in the dialogue. Maybe mkarcher only set you the BIOS with IRQ routing table fixes?

I recall having a lot of trouble getting the G450 running on several socket 3 mainboards. Could you let me know which display driver versions you were able to get working in Windows 2000 and Win9x? Did you also test to ensure that D3D and OpenGL were working properly?

feipoa wrote on 2023-02-19, 07:51:

Thanks for your reply. It was not clear to me from the PS/2-HOT433 thread that mkarcher fixed the IRQ routing table in his BIOS patch of 2A4X5H21. I could not locate any mention of it in the dialogue. Maybe mkarcher only set you the BIOS with IRQ routing table fixes?

I recall having a lot of trouble getting the G450 running on several socket 3 mainboards. Could you let me know which display driver versions you were able to get working in Windows 2000 and Win9x? Did you also test to ensure that D3D and OpenGL were working properly?

May you check whether you have these problems just at 40 MHz FSB or at 33 MHz too?
We've examined that the PCI-to-AGP bridge is sometimes not initialized properly when the PCI clock is too low. And on the HOT 433 the PCI clock runs at half clock in the very early initialisation phase on FSB 40!

feipoa wrote on 2023-02-19, 07:51:

Thanks for your reply. It was not clear to me from the PS/2-HOT433 thread that mkarcher fixed the IRQ routing table in his BIOS patch of 2A4X5H21. I could not locate any mention of it in the dialogue. Maybe mkarcher only set you the BIOS with IRQ routing table fixes?

I'm sorry for any confusion about the IRQ routing. The 2A4X5H21 BIOS does not need a patched IRQ routing table. The talk about the fixing the IRQ rouing table was at the time we were using a BIOS image meant for a different UMC8881 board, with the ID 2A4X5G03. As the IRQ routing table is board specific, it is no surprise that the IRQ routing table from the "foreign" BIOS did not match the HOT-433. When we added the PS/2 mouse port, we found the updated HOT-433 BIOS (most likely a unofficial community build?) with the ID 2A4X5H21. This BIOS already contains the correct IRQ routing table, so no patch is required.

Yet, even with the BIOS with the correct IRQ routing table, the board turned out to be very picky about UDMA IDE controllers. We tried a Promise FastTrack controller, a Silicon Image controller and the Highpoint controller. The only controller that managed to run reliably was the HighPoint controller, and even that controller doesn't do busmaster transfers reliably at PCI@20. You don't need a BIOS patch to fix that issue, because no IDE busmaster transfers are performed before the CMOS settings are applied. Furthermore, even with the HighPoint controller, we experienced intermittent data corruption when L2 writeback is enabled. As L2WT is required, we are operating with 256MB of RAM, which is fully cached by the 1MB L2 cache.

Our HOT-433 uses an early revision of the UMC chipset (without EDO support), so maybe some of the difficulties are resolved with later revisions. Unfortunately, I don't remember whether we tested all those issues on the Biostar MB-8433UUD we have. That one has a newer UMC chipset revision.