diff --git a/DuetPkg/DxeIpl/SerialStatusCode.c b/DuetPkg/DxeIpl/SerialStatusCode.c
index 77b26690f8..5537377448 100644
--- a/DuetPkg/DxeIpl/SerialStatusCode.c
+++ b/DuetPkg/DxeIpl/SerialStatusCode.c
@@ -695,7 +695,7 @@ Returns:
   CHAR8                   *Filename;
   CHAR8                   *Description;
   CHAR8                   *Format;
-  VA_LIST                 Marker;
+  BASE_LIST               Marker;
   UINT32                  ErrorLevel;
   UINTN                   CharCount;
 
@@ -720,7 +720,7 @@ Returns:
     //
     // Process PEI_DEBUG () macro to Serial
     //
-    AsciiVSPrint (Buffer, EFI_STATUS_CODE_DATA_MAX_SIZE, Format, Marker);
+    AsciiBSPrint (Buffer, EFI_STATUS_CODE_DATA_MAX_SIZE, Format, Marker);
 
   } else if ((CodeType & EFI_STATUS_CODE_TYPE_MASK) == EFI_ERROR_CODE) { 
     //
diff --git a/DuetPkg/Library/DxeCoreReportStatusCodeLibFromHob/ReportStatusCodeLib.c b/DuetPkg/Library/DxeCoreReportStatusCodeLibFromHob/ReportStatusCodeLib.c
index 71606143f1..c8268c7de6 100644
--- a/DuetPkg/Library/DxeCoreReportStatusCodeLibFromHob/ReportStatusCodeLib.c
+++ b/DuetPkg/Library/DxeCoreReportStatusCodeLibFromHob/ReportStatusCodeLib.c
@@ -229,14 +229,14 @@ EFIAPI
 ReportStatusCodeExtractDebugInfo (
   IN CONST EFI_STATUS_CODE_DATA  *Data,
   OUT UINT32                     *ErrorLevel,
-  OUT VA_LIST                    *Marker,
+  OUT BASE_LIST                  *Marker,
   OUT CHAR8                      **Format
   )
 {
   EFI_DEBUG_INFO  *DebugInfo;
 
-  ASSERT (Data       != NULL);
-  ASSERT (ErrorLevel != NULL);
+  ASSERT (Data          != NULL);
+  ASSERT (ErrorLevel    != NULL);
   ASSERT (Marker     != NULL);
   ASSERT (Format     != NULL);
 
@@ -258,7 +258,7 @@ ReportStatusCodeExtractDebugInfo (
   // The first 12 * UINTN bytes of the string are really an
   // argument stack to support varargs on the Format string.
   //
-  *Marker = (VA_LIST) (DebugInfo + 1);
+  *Marker = (BASE_LIST) (DebugInfo + 1);
   *Format = (CHAR8 *)(((UINT64 *)*Marker) + 12);
 
   return TRUE;