digraph G {
    rom [label = "CPU Rom Code";shape = rect;];
    
    uboot [label = "u-boot with EFI/EBBR support";shape = rect;];
    
    btl [label = "EFIBootGuard";shape = rect;];

    kernel [label = "OS (EFI Stub + Kernel + Initramfs";shape = rect;];
    
    rom -> uboot -> btl -> kernel;
}