FIXED WITHOUT DESOLDERING BIOS.
Update for anyone in the future who has same bitrot issue with the Diamond Stealth II G460 AGP (Intel i740). It was a pain to find the correct file, but someone had the original Diamond flash files on an FTP after some sleuthing.
https://ftp.zx.net.nz/pub/archive/ftp.dyu.edu … 60/flash114.exe
https://ftp.zx.net.nz/pub/archive/ftp.dyu.edu … 60/460nt115.exe
https://ftp.zx.net.nz/pub/archive/ftp.dyu.edu … 60/flash116.exe
1.) FTP links are listed above for 1.14/1.15/1.16 BIOS files (Mine was a 1.14)
2.) Format a floppy disk, copy the system files to make it bootable
3.) Run the executable, it will copy vflash.exe, the BIOS, RAMI740 and a few other files to the disk
4.) Boot with just the broken card (no secondary card is needed) as it loads the VGA BIOS into RAM, as specified in the copied AUTOEXEC.BAT file because the RAMI740 loads the VGA BIOS into RAM
5.) At which point, your display should turn on once the RAMI740.exe is loaded
6.) The vflash process will then start and the VGA BIOS will then be flashed to the video card
7.) Reboot and works like a charm now, no desoldering needed.