Have been able to find the Tyan BIOS on their FTP 😀

No success on the others.

Great! PIII-1000 booted just fine!
Thank You, PcBytes

Here is the pic of Iwill / Quick Technology Inc. 586 SP v0.2 in case someone have this board.
http://f5soft.com/pics/2018-05/1.JPG

I found this mobo without BIOS chip. I copied BIOS from ASUS board with same chicest but new BIOS fails to initialize PCI bus. So i can use only ISA slots.

BreakPoint wrote:

Here is the pic of Iwill / Quick Technology Inc. 586 SP v0.2 in case someone have this board.
http://f5soft.com/pics/2018-05/1.JPG

I found this mobo without BIOS chip. I copied BIOS from ASUS board with same chicest but new BIOS fails to initialize PCI bus. So i can use only ISA slots.

That's actually a EPOX board, P54C-SP to be exact.

Couldn't find the BIOS for it, or for anything else than ASUS for that matter (and BCM.)

Looks like the EpoX P5-SP (it's shown in the same manual as the P54C-SP, but the Socket 4 version is the P5-SP).

Here's the file I have with pieces of the manual, but I didn't find a BIOS with a filename to match.
If somebody has a BIOS for either the P5-SP (socket 4) or the P54C-SP (socket 5), maybe both would work. The differences between the boards are probably minimal.

The manual file is also at the "mobokive" currently at http://www.elhvb.com.
Maybe there's an IWill version, but I looked at the IWill section of that site and it didn't look like they have anything for it.