diff --git a/DuetPkg/DxeIpl/Debug.c b/DuetPkg/DxeIpl/Debug.c
index 950c06b118..1cb7e39c80 100644
--- a/DuetPkg/DxeIpl/Debug.c
+++ b/DuetPkg/DxeIpl/Debug.c
@@ -77,6 +77,6 @@ PrintString (
   //
   // All information also output to serial port.
   //
-  SerialPortWrite (PrintBuffer, Index);
+  SerialPortWrite ((UINT8 *) PrintBuffer, Index);
 }
 
diff --git a/DuetPkg/DxeIpl/SerialStatusCode.c b/DuetPkg/DxeIpl/SerialStatusCode.c
index 27e8644b38..1595932383 100644
--- a/DuetPkg/DxeIpl/SerialStatusCode.c
+++ b/DuetPkg/DxeIpl/SerialStatusCode.c
@@ -675,7 +675,7 @@ Returns:
     //
     // Callout to platform Lib function to do print.
     //
-    SerialPortWrite (Buffer, CharCount);
+    SerialPortWrite ((UINT8 *) Buffer, CharCount);
   }
 
   //
@@ -727,7 +727,7 @@ Returns:
           Instance
           );
 
-        SerialPortWrite (Buffer, CharCount);
+        SerialPortWrite ((UINT8 *) Buffer, CharCount);
       }
     }