coreboot-kgpe-d16/Documentation/flash_tutorial/int_flashrom.md

Flashing firmware internally

WARNING: If you flash a broken firmware and have no recovery mechanism, you must use the external method to flash a working firmware again.

Using flashrom

This method does only work on Linux, if it isn't locked down. You may also need to boot with iomem=relaxed in the kernel command line if CONFIG_IO_STRICT_DEVMEM is set.

For more details please also check flashrom's wiki. Use the programmer internal to flash coreboot.rom internally:

flashrom -p internal -w coreboot.rom