diff --git a/Outputs/CRT.cpp b/Outputs/CRT.cpp
index b44f39e5b..7a77a90f2 100644
--- a/Outputs/CRT.cpp
+++ b/Outputs/CRT.cpp
@@ -409,7 +409,8 @@ void CRTFrameBuilder::reset()
 {
 	frame.number_of_runs = 0;
 	_next_write_x_position = _next_write_y_position = 0;
-	frame.dirty_size.width = frame.dirty_size.height = 0;
+	frame.dirty_size.width = 0;
+	frame.dirty_size.height = 1;
 }
 
 void CRTFrameBuilder::complete()
diff --git a/Outputs/CRT.hpp b/Outputs/CRT.hpp
index f08b018cf..ff17be013 100644
--- a/Outputs/CRT.hpp
+++ b/Outputs/CRT.hpp
@@ -41,7 +41,7 @@ struct CRTFrameBuilder {
 		// returned and to where the next section will begin
 		uint16_t _next_write_x_position, _next_write_y_position;
 		uint16_t _write_x_position, _write_y_position;
-		unsigned int _write_target_pointer;
+		size_t _write_target_pointer;
 };
 
 static const int kCRTNumberOfFrames = 4;