Hello !

For Banshee & Voodoo3
on this web page
http://www.v3info.de/english/html/downloads.shtml
you will find a recovery disk and the EXACT procedure to recover from a failed BIOS Update.

For Banshee only
ftp://ftp.guillemot.com/video/exe/PHX/
This is for Guillemot Maxi Gamer Phoenix, but should work for most Banshee boards because these are generic BIOS & drivers from 3dfx
bgp9x110.exe creates a bootdisk that is able to revive a banshee board, but WARNING : it contains a TSR BIOS for SGRAM (not SDRAM)

latest 3dfx official Banshee ROM BIOS & TSR BIOS
http://www.geocities.com/bansheedrivers/page4.html

TSR BIOS is a Terminate & Stay Resident small DOS program that contains a BIOS image and loads it so that you see the DOS screen again

Best regards