I tried to update the BIOS firmware on this board (the GIGABYTE MZ242-G20 in a G292-Z40 chassis) using `flashrom -pinternal`. This did not work, as it failed to find an appropriate erase function. I subsequently re-flashed using the BMC, which recovered the machine. Investigating the .bin files at the various stages, it appears that the erase did actually work, except that regions below 0x01000000 always read back as 0xFF under flashrom (while a proper SPI readback over the BMC shows this not to be the case). This board is an AMD Zen3 mainboard so the flasher in question is sb600. Looking at the image, I believe the regions above and below 0x01000000 are used as part of a dual bios setup, as they are substantially identical. Perhaps there are some protection registers in the SPI bus master that flashrom needs to be aware of in order to properly read this SPI flash?
Keno