Platform Initialization Firmware Phases EDK II - stages time coreboot - stages Security (SEC) Pre-EFI Initialization Environment (PEI) Driver Execution Environment (DXE) Boot Device Selection (BDS) bootblock romstage verstage (optional) postcar (x86 only) ramstage SMM (x86 only) payload Assembly Cache-As-RAM DRAM C ADA SPARK (x86 only) coreboot source languages code/heap memory location BL31 (ARM only) Power on