Methods, systems and program products provide platform customization in building of Unified Extensible Firmware Interface based Personal Computer firmware, typically but not essentially as BIOS. Provision is made for a conceptual matrix of Board module, Silicon (or chipset) modules together with core and foundation modules; this supersedes prior approaches that are often based on hierarchical (or inverse hierarchy) structured source codes. A Platform module resides architecturally between Silicon and Board modules. By largely removing the Platform module found in previously developed solutions and introducing a Board module OEM, customizations are separated from actual platform code (and also from core functions). This allows the customization footprint to be much smaller thus easing the programming efforts of porting products to reflect hardware development.