typedef struct _LOADER_PARAMETER_BLOCK
{
     LIST_ENTRY LoadOrderListHead;
     LIST_ENTRY MemoryDescriptorListHead;
     LIST_ENTRY BootDriverListHead;
     ULONG KernelStack;
     ULONG Prcb;
     ULONG Process;
     ULONG Thread;
     ULONG RegistryLength;
     PVOID RegistryBase;
     PCONFIGURATION_COMPONENT_DATA ConfigurationRoot;
     CHAR * ArcBootDeviceName;
     CHAR * ArcHalDeviceName;
     CHAR * NtBootPathName;
     CHAR * NtHalPathName;
     CHAR * LoadOptions;
     PNLS_DATA_BLOCK NlsData;
     PARC_DISK_INFORMATION ArcDiskInformation;
     PVOID OemFontFile;
     _SETUP_LOADER_BLOCK * SetupLoaderBlock;
     PLOADER_PARAMETER_EXTENSION Extension;
     BYTE u[12];
     FIRMWARE_INFORMATION_LOADER_BLOCK FirmwareInformation;
} LOADER_PARAMETER_BLOCK, *PLOADER_PARAMETER_BLOCK;

Windows Vista Kernel Structures