Gateway 2000 Mobo BOIS
Yes, soldered chip. That's why the easiest option I could think of was forcing a checksum error - the bootblock BIOS would start with A16, A17 high (top 64k) and access the rest of BIOS to do the checksum. By detecting A16 or A17 low and pulling a data line low with an open-collector buffer, maybe you can force a checksum error and cause the bootblock recovery procedure to be invoked. Not that I have tried this yet, you understand 

I use screwdriver method to force a checksum error sometimes. Using a small screwdriver, short two topmost address pins and power up. After getting BIOS checksum error, remove the screwdriver and flash.
I fixed QDI Titanium IB+ board that was flashed with Titanium IB BIOS and hanged during POST (different Super I/O - so I needed ISA FDC too).
I fixed QDI Titanium IB+ board that was flashed with Titanium IB BIOS and hanged during POST (different Super I/O - so I needed ISA FDC too).
Patched and tested BIOSes are at http://wims.rainbow-software.org
UniFlash - Flash anything anywhere
UniFlash - Flash anything anywhere