Try uniflash http://www.win3x.org/win3board/viewtopic.php?f=22&t=19455

It's a fantastic tool that lets you write any ROM file you want with any motherboard you want (as long as it's capable of flashing bioses)

Thanks Deksor,
Decided to give it a try --

It doesn't work from Windows
OK ---> loaded via AUTOEXEC.BAT
Write 1012tctwkb2.002 (custom BIOS) INCLUDING bootblock (default) ---> Progress-bar filled up with red blocks, with two green areas at around 70-90%, verify failed, repeat y/n? ---> Reboot successful.
Write 1014tc.001 (official version) again INCLUDING bootblock (default) ---> Progress-bar filled up with green blocks, with one red area at around 90%, again verify failed, repeat y/n? Reboot successful.

Was it only Verify stage (no Write was performed)?

Fix the floppy drive issue first! Early windows based flashers were not safe and I had to do it via floppy drive back in the day.

Cheers,

Well you need to use uniflash from DOS.
Can't you reboot to MS-DOS mode or something ?
Or use a windows 98 OEM install cd, they boot your pc to MS-DOS 7.1 which is perfectly fine.

For flashing BIOS i use separate bootable HDD with just DOS stripped from 98SE and some DOS based utilities for partitioning, diagnoctics, etc.

_UV_ wrote on 2020-11-01, 01:34:

For flashing BIOS i use separate bootable HDD with just DOS stripped from 98SE and some DOS based utilities for partitioning, diagnoctics, etc.

Good suggestion ! Was thinking that while reading this. If you do not have a good working floppy or cannot get to a "good" DOS type boot (WinME, XP, Vista, etc do not have it) on an older machine then this is a good alternative.
Win9x you can hit F8 while booting and choose "Safe Mode with Command Prompt" but some OEM installs and tweaked versions do not work that way...

Got a spare floppy drive. Checked diskettes I had -- with same result (most disks were unreadable, only specific one had all files intact) as when using the previous drive. It means the drives themselves (even the old one) were in working condition, and it were my diskettes partially or completely corrupted (though I still could format them and write some specific amount of data -- which even passed subsequent md5 checks).
Created bootable diskette using WinXP (yes, I know) -- it booted.
I decided not to risk and not to copy the flash utility and an image to the diskette (because it might corrupt), so I copied the flashing utility and the firmware image to the HDD, booted from floppy, opened the program on the HDD and flashed my BIOS successfully.
Thanks for help!

Get another set of floppy disks. I like 3M best as long as it is sealed.

Old disks that were sitting too long especially poor quality ones tend to degrade prematurely.

Cheers,