diff --git a/include/winternl.h b/include/winternl.h
index cbf5c669c86..8ccbfd7c9bb 100644
--- a/include/winternl.h
+++ b/include/winternl.h
@@ -1579,6 +1579,23 @@ typedef struct _SYSTEM_TIME_ADJUSTMENT {
     BOOLEAN TimeAdjustmentDisabled;
 } SYSTEM_TIME_ADJUSTMENT, *PSYSTEM_TIME_ADJUSTMENT;
 
+typedef enum _SYSTEM_FIRMWARE_TABLE_ACTION
+{
+    SystemFirmwareTable_Enumerate = 0,
+    SystemFirmwareTable_Get = 1
+} SYSTEM_FIRMWARE_TABLE_ACTION, *PSYSTEM_FIRMWARE_TABLE_ACTION;
+
+/* System Information Class 0x4C */
+
+typedef struct _SYSTEM_FIRMWARE_TABLE_INFORMATION
+{
+    ULONG ProviderSignature;
+    SYSTEM_FIRMWARE_TABLE_ACTION Action;
+    ULONG TableID;
+    ULONG TableBufferLength;
+    UCHAR TableBuffer[1];
+} SYSTEM_FIRMWARE_TABLE_INFORMATION, *PSYSTEM_FIRMWARE_TABLE_INFORMATION;
+
 typedef struct _TIME_FIELDS
 {   CSHORT Year;
     CSHORT Month;