Stumbled across this. Seems to be a unsolved mystery and also looks like the free style bios might be the trick.

ADI TK8881 board cpu setting

You are correct, it's almost impossible to find anything out there about this.
Most likely it will have a non flashable Eprom fitted. Even if it has a flashable one, unless You have an eprom programmer, leave it alone
or you might kill it.

I patched my 4DPS bios to support 40gig hdd, but as I have a programmer there is no risk. If you have a programmer upload the
bios here and I'll see if I can patch it with "Biospatcher" and "Modbin"

Imperious wrote:

You are correct, it's almost impossible to find anything out there about this. Most likely it will have a non flashable Eprom fi […]
Show full quote

You are correct, it's almost impossible to find anything out there about this.
Most likely it will have a non flashable Eprom fitted. Even if it has a flashable one, unless You have an eprom programmer, leave it alone
or you might kill it.

I patched my 4DPS bios to support 40gig hdd, but as I have a programmer there is no risk. If you have a programmer upload the
bios here and I'll see if I can patch it with "Biospatcher" and "Modbin"

non flashable EPROM

that's like saying un drinkable potable water

Ampera wrote:

non flashable EPROM

that's like saying un drinkable potable water

Actually the BIOS on most 486 motherboards is not stored on a flash ROM, instead they use UV-erasable EPROMs which are NOT a type of flash memory.

Only on certain (later) 486 boards you can flash the BIOS using the appropriate utility from AMI/Award/etc. , that's why Imperious suggests not messing with it unless using a programmer.

http://www.differencebetween.com/difference-b … -and-vs-eeprom/

[edited]

I suspect the BIOS from most PCI 486 motherboards containing UM8881F, UM8886AF, and UM8663AF chipsets will work on your board.

Your board is very similar to a Gigabyte GA486AM/S, however it looks like your board only supports up to 512K single-banked cache, while the GA486AM/S supports up to 1024K double-banked cache. This is merely a manifestation of the quantity of pins the manufacturer used on the cache DIP sockets and can be altered if desired, e.g. Re: The World's Fastest 486

Why are you looking for another BIOS? Boards with the UM8666BF were more likely to have BIOS updates. I'm still not sure what the difference between the AF and BF are, but I suspect the BF added PS/2 mouse support (I have zero evidence to back this up, just general observations).

PARKE wrote:

UV erasable chips are EEPROMS, the types that can be flashed via software are EPROMS.

http://www.differencebetween.com/difference-b … -and-vs-eeprom/

You've got those the wrong way round.

TheMobRules wrote:

Ampera wrote:

non flashable EPROM

that's like saying un drinkable potable water

Actually the BIOS on most 486 motherboards is not stored on a flash ROM, instead they use UV-erasable EPROMs which are NOT a type of flash memory.

Only on certain (later) 486 boards you can flash the BIOS using the appropriate utility from AMI/Award/etc. , that's why Imperious suggests not messing with it unless using a programmer.

I am well aware of this. For whatever reason in my mind I thought the act of writing to a PROM was called flashing.

I need to get myself a PROM burner one of these days as it's more useful the older you go into computing.

Imperious wrote:

You are correct, it's almost impossible to find anything out there about this. Most likely it will have a non flashable Eprom fi […]
Show full quote

You are correct, it's almost impossible to find anything out there about this.
Most likely it will have a non flashable Eprom fitted. Even if it has a flashable one, unless You have an eprom programmer, leave it alone
or you might kill it.

I patched my 4DPS bios to support 40gig hdd, but as I have a programmer there is no risk. If you have a programmer upload the
bios here and I'll see if I can patch it with "Biospatcher" and "Modbin"

Thank you that would be great. I do not have one but have been thinking about getting one.... I will let you know

Update - Both Imperious and feipoa were correct. This board does have a "Non Flashable EPROM". There is a jumper when clearing CMOS and Programming the EPROM to use 5V or 12V. Feipoa was also correct, kinda. So I also have one of the infamous PC Chips 919 boards with the fake cache chips on it. So I pulled the BIOS out of it (AMI) and installed it on this mystery board (Award) and to my surprise it booted, count all 128MB of EDO RAM and gave me a CHECKSUM error. I entered the BIOS and fixed the clock and auto detected the HD as a 8GB instead of 2 GB which was one of the goals! But when I exited and saved changes it never came back so I had to put the old BIOS back in.

The BIOS out of the PC Chips board has been flashed with a BIOS version from 04/15/1996, the BIOS in the mystery board is dated -7/15/1995. I would just use the PC Chips board if I could find a COAST cache stick.

Another note, the PC Chips board os a BF chipset and the mystery board is a AF. I'm not sure of the difference either except that the BF had support for a PS/2 mouse.

I'll keep playing with it but thought this was an interesting outcome just switching an Award BIOS with an AMI BIOS from different boards with different chip sets and it did anything.

spaceghost711 wrote:

Update - Both Imperious and feipoa were correct. This board does have a "Non Flashable EPROM". There is a jumper when clearing CMOS and Programming the EPROM to use 5V or 12V.

Why would a board provide programming option for EPROM? So you turn on the machine, shine UV-light on it overnight and then start updating the BIOS?
Please do us a favor - lift the sticker and report back the model number on the BIOS chip.

Will do

lazibayer wrote:

spaceghost711 wrote:

Update - Both Imperious and feipoa were correct. This board does have a "Non Flashable EPROM". There is a jumper when clearing CMOS and Programming the EPROM to use 5V or 12V.

Why would a board provide programming option for EPROM? So you turn on the machine, shine UV-light on it overnight and then start updating the BIOS?
Please do us a favor - lift the sticker and report back the model number on the BIOS chip.

Here you go! Sorry it took so long. Been working on Windows ME and my PCChips 919 board. I know, ME.... don't judge. Finally got it installed though.

spaceghost711 wrote:

lazibayer wrote:

spaceghost711 wrote:

Update - Both Imperious and feipoa were correct. This board does have a "Non Flashable EPROM". There is a jumper when clearing CMOS and Programming the EPROM to use 5V or 12V.

Why would a board provide programming option for EPROM? So you turn on the machine, shine UV-light on it overnight and then start updating the BIOS?
Please do us a favor - lift the sticker and report back the model number on the BIOS chip.

Here you go! Sorry it took so long. Been working on Windows ME and my PCChips 919 board. I know, ME.... don't judge. Finally got it installed though.

Could you dump that bios and post it here please? Hd limitations are not a problem. I have the exact same board but without any bios chip so a dump would be great!
That way i can finally test it and see if it works. Any directions to a fully working )other ) bios is also fine. Thanks!

i have a question regarding bios flashing on old 486 PC
For example i have an pcCheaps m919 motherboard that has a jumper that says

Flash ROM Voltage Selector
Description JP2

12 volt Flash ROM : short pin 1-2
5 volt Flash ROM : short pin 2-3

What is this? I have no jumper at all in there and the board works.
i have no clue of what it is for, i always thought you needed an external rom flasher for these.

Cga.8086 wrote:

i have a question regarding bios flashing on old 486 PC For example i have an pcCheaps m919 motherboard that has a jumper that s […]
Show full quote

i have a question regarding bios flashing on old 486 PC
For example i have an pcCheaps m919 motherboard that has a jumper that says

Flash ROM Voltage Selector
Description JP2

12 volt Flash ROM : short pin 1-2
5 volt Flash ROM : short pin 2-3

What is this? I have no jumper at all in there and the board works.
i have no clue of what it is for, i always thought you needed an external rom flasher for these.

The jumper decides whether to send 12V to pin 1 of the flash chip when programming. Pin 1 is NC on 5V chips. So in your case, you have no problem reading or writing a 5V chip, but you can only read a 12V chip unless you supply 12V manually to its pin 1.

lazibayer wrote:

Cga.8086 wrote:

i have a question regarding bios flashing on old 486 PC For example i have an pcCheaps m919 motherboard that has a jumper that s […]
Show full quote

i have a question regarding bios flashing on old 486 PC
For example i have an pcCheaps m919 motherboard that has a jumper that says

Flash ROM Voltage Selector
Description JP2

12 volt Flash ROM : short pin 1-2
5 volt Flash ROM : short pin 2-3

What is this? I have no jumper at all in there and the board works.
i have no clue of what it is for, i always thought you needed an external rom flasher for these.

The jumper decides whether to send 12V to pin 1 of the flash chip when programming. Pin 1 is NC on 5V chips. So in your case, you have no problem reading or writing a 5V chip, but you can only read a 12V chip unless you supply 12V manually to its pin 1.

But you still need an external flasher to change the bios right?
when was auto DOS flashing utility appeared in history? in the pentium3 era ?

Cga.8086 wrote:

lazibayer wrote:

Cga.8086 wrote:

i have a question regarding bios flashing on old 486 PC For example i have an pcCheaps m919 motherboard that has a jumper that s […]
Show full quote

i have a question regarding bios flashing on old 486 PC
For example i have an pcCheaps m919 motherboard that has a jumper that says

Flash ROM Voltage Selector
Description JP2

12 volt Flash ROM : short pin 1-2
5 volt Flash ROM : short pin 2-3

What is this? I have no jumper at all in there and the board works.
i have no clue of what it is for, i always thought you needed an external rom flasher for these.

The jumper decides whether to send 12V to pin 1 of the flash chip when programming. Pin 1 is NC on 5V chips. So in your case, you have no problem reading or writing a 5V chip, but you can only read a 12V chip unless you supply 12V manually to its pin 1.

But you still need an external flasher to change the bios right?
when was auto DOS flashing utility appeared in history? in the pentium3 era ?

It appeared no later than 486 era, because I have done that on a couple of 486 boards. It became dominant in the pentium era.
Even if you can't get your board to program its BIOS, you may also use Intel, 3COM or Realtek NIC cards with 32pin socket to program most 128KB or smaller flash chips.

Could you make a small guide about how to do that exactly @Lazybayer? Because i hear that a lot but can not find any guide/info about it on the net other than uniflash can do it.

I use the hotflash method (works also great) on a pentium1 motherboard for all 128kb and 256kb bioss files but what if i use a ethernet card in that same board, can i choose which chip uniflasher should read/use between the one on the motherboard and the one on the card?

meljor wrote:

Could you make a small guide about how to do that exactly @Lazybayer? Because i hear that a lot but can not find any guide/info about it on the net other than uniflash can do it.

I use the hotflash method (works also great) on a pentium1 motherboard for all 128kb and 256kb bioss files but what if i use a ethernet card in that same board, can i choose which chip uniflasher should read/use between the one on the motherboard and the one on the card?

I use Flashrom for the job. They have detailed documentation for supported EEPROM chips, NIC cards, motherboards, video cards, etc.
The latest stable (ver. 0.9.9) DOS release can be found here. You also need to put CWSDPMI.EXE under the same folder.