coreboot* is an open source firmware project, describing a phase-based initialization infrastructure for Intel® architecture and other processor architectures. The coreboot platform initializes system hardware then launches a payload, which loads the operating system or other system applications.
Intel architecture platforms using coreboot are commonly enabled using the Intel® Firmware Support Package (Intel® FSP). Intel FSP provides silicon initialization ingredients for an open source framework.
More Information
Firmware Flexibility Using the Intel® Firmware Support Package (IDF 2014, PDF)