diff --git a/src/mess/includes/sapi1.h b/src/mess/includes/sapi1.h
index 81ccce9837b..3bb9bbddca6 100644
--- a/src/mess/includes/sapi1.h
+++ b/src/mess/includes/sapi1.h
@@ -53,7 +53,7 @@ public:
 	UINT32 screen_update_sapizps3(screen_device &screen, bitmap_ind16 &bitmap, const rectangle &cliprect);
 
 protected:
-	required_memory_bank m_bank1;
+	optional_memory_bank m_bank1;	// Only for sapi3
 	required_ioport m_line0;
 	required_ioport m_line1;
 	required_ioport m_line2;