We should perhaps have read this thread Im linking before we flashed our ASUS PVI-486SP3 boards with the newest 0307 PNP BIOS...
Asus PVI-486SP3 BIOS issues

I did the same mistake as many others and flashed the dreaded Intel P28F010 12v flash chip with the latest 0307 PNP BIOS and I got the same issues. I reverted back to the old 0203 non PNP BIOS and everything seems fine again so at least my system diddnt get messed up like Turbomans. I used Uniflash, I pretty much only use Uniflash with older systems as my experience of most other flash programs are ... not very good.

The conclusion is that the last BIOS version you can use with a 12V flash chip is 0205 as newer BIOS versions dropped support for 12V flash chips.

There is yet another thing to look out for, if your SIS chipset revision is A4 you can not use any 030x BIOS regardless of flash chip but 0205 should work. I hope someone else can confirm.

Here is the latest PNP BIOS for those with 5V flash chip AND B revison SIS chipset

Here is Uniflash

Here is a link to a FTP as Asus dosnt host these BIOS files any more.
ftp://ftp.tekwind.co.jp/pub/asustw/mb/sock5/486sp3/

Perhaps someone with access to VOGONS Vintage Driver Library can upload everything in that directory to the driver archive as a single zip file.