This thread had a J-446A, and someone was kind enough to post the BIOS for it. Maybe that's close enough to work? BIOS for Jetway j446a ver 2.0

You could try that BIOS with a bootblock flash, not much to lose at this point. https://www.birdjanitor.com/bootblock.html

I have a working board like that - the only info on the silkscreen it has is "J446B"between the first and second PCI slots, so it may as well be the same model. BIOS is an Award. Only problem is that I don't have a TL866 or any hardware dumping tool for it 🙁 I'll try AWDFLASH and let you know if I manage to get a dump of it.

kikipcs wrote on 2022-01-03, 10:48:

I have a working board like that - the only info on the silkscreen it has is "J446B"between the first and second PCI slots, so it may as well be the same model. BIOS is an Award. Only problem is that I don't have a TL866 or any hardware dumping tool for it 🙁 I'll try AWDFLASH and let you know if I manage to get a dump of it.

Uniflash might be worth a shot if Award doesn't work. https://www.download3k.com/System-Utilities/O … d-UniFlash.html

Thank you all for the information! So far the board isn't booting *anything* from two known good floppy drives and a variety of tested working boot disks, I have a TL866 2 Plus (I think) on order and a 'tested working' other board, the plan is to nab the bios image from the other board. The bios image for the A version might work, once I am able to get that on a chip I will let you know. I will also have youtube videos documenting the attempts on this board, but not sure if it is prudent or allowed to post such links here.

Again many thanks!

"and a variety of tested working boot disks"

Just to be 100% sure, you did try the edited autoexec.bat detailed in the link for the bootblock flash?

I have not, i will try it, but will a UV erasable eprom flash through software? we shall find out

animegaud wrote on 2022-01-05, 00:40:

I have not, i will try it, but will a UV erasable eprom flash through software? we shall find out

That is a question I can't answer, but there are people on this board who would know.

Thanks, I tried a floppy formatted in Windows 95 with system files added, made an AUTOEXEC.BAT file to match the instructions posted above, it did not boot, states it is an invalid boot disk, though according to floppy drive sounds I don't think it is trying to read the disk at all

after several reboots, it sure does try once in a while but so far no luck or joy, I will keep this post informed

Hello,

After some battling I managed to dump the BIOS and CMOS settings, using UNIFLASH.
The dump looks fine in HxD, and when I set up a machine in 86box using the bios, it booted fine! See below:

Please find the ROM and the CMOS settings in the attachment. I will also try to upload them on the VOGONS Drivers library.
Let me know if that helped you, cheers!

**edit** nevermind I'm not able to upload anything to VOGONS Drivers. I hope the attachment here will serve you well.

Seeing this is a SiS496 board, I hope you either have a B5 revision of the chipset (PR) if using EDO ram or using FPM RAM if a lower revision becuase they don't like EDO.

Nice Kikipcs, thanks! I don't have a chip i can write that to at current. I have obtained a second Jetway J446B board because i'm crazy and am going to try some chip swapping, and will copy the rom off of this one and link it here too. Can never have too much eh?

I got the bios image from the working board saved as a .bin file for those who may find it useful (and those who can see if I did this right heh)
Thanks to everyone for their help

I attempted to boot the first (beaten stepchild) board with the BIOS EEPROM from the newly aquired board and it booted into the Award BootBlock again. Conversely, for science, I tried the UV EPROM Bios from the first in the new board and that booted without issue .. the problem lies somewhere else

The POST screen from the UV-EPROM (the one I originally thought to be bad) is J446Bold.jpg
The POST screen form the EEPROM from the newly obtained board's BIOS is J446Bnew.jpg
Only minor differences in them, I can save and upload the .bin for the other as well if anyone would like it

Good to see you doing progress - and kudos on getting another of the same mobo! 😁

The BIOSes you provided seem to be the latest ones with a date of 24 Dec 1996 - I'm keen to learn what changes were made in relation to the older versions.

animegaud wrote on 2022-01-10, 23:07:

The POST screen from the UV-EPROM (the one I originally thought to be bad) is J446Bold.jpg
The POST screen form the EEPROM from the newly obtained board's BIOS is J446Bnew.jpg
Only minor differences in them, I can save and upload the .bin for the other as well if anyone would like it

Great that you tried the old BIOS in the new board and it worked! And the new BIOS in the old board failed as well, most curious.
Usually a boot into the Bootblock signals a corrupt BIOS, but not in this case...

These BIOSes are compressed and contain a decompression engine that decompresses all BIOS modules into RAM. After an integrity test, these modules are then copied to their allocated position in shadow RAM, and are run to do the POST.
If the integrity checks fails, the decompression engine jumps to the bootblock to start a possible BIOS recovery from floppy.

Because this whole process is done in RAM, what if there is a problem in the memory system? This could cause a memory corruption that would trip the integrity check with the same outcome of a bootblock recovery.
So this is where I would look on the old board. Flacky RAM? Corroded SIMM slots? Bad caps causing ripples on the supply lines to the memory system?
Hopefully, you find something there.

Yes, I like to see the bin from the old J446B board as well. Then I can tell you what the differences are.

Good hunting!
Jan

Ah, thank you Jan! I hadn't considered memory so didn't try changing that! I put the memory from the new board on the old board with no other change and .. it fired right up! The ram was the issue! After some investigation, I believe it was because the memory i was using on the old board is EDO and the board didn't quite know what to do with it. The old bios is attached.

Again many thanks! Now for the other issues. This board was rather abused, bent pins, memory latches are broken, broken traces.. but it's a fighter!

Thanks for the BIOS and boot screens, can you take a good picture of your board ?
have nothing better to add but am grateful for any extra info you have