diff --git a/parallel-rdp/interface.cpp b/parallel-rdp/interface.cpp
index 10cfbb5..697d898 100644
--- a/parallel-rdp/interface.cpp
+++ b/parallel-rdp/interface.cpp
@@ -61,7 +61,7 @@ static int cmd_cur;
 static int cmd_ptr;
 static CALL_BACK callback;
 static GFX_INFO gfx_info;
-static int32_t region;
+static uint32_t region;
 static bool crop_letterbox;
 static const uint32_t *fragment_spirv;
 static size_t fragment_size;
@@ -592,9 +592,14 @@ uint64_t rdp_process_commands()
 			uint32_t upper_left_y = (w1 & 0xFFF) >> 2;
 			uint32_t lower_right_x = ((w2 >> 12) & 0xFFF) >> 2;
 			uint32_t lower_right_y = (w2 & 0xFFF) >> 2;
-			region = (lower_right_x - upper_left_x) * (lower_right_y - upper_left_y);
-			if (region < 0)
+			if (lower_right_x > upper_left_x && lower_right_y > upper_left_y)
+			{
+				region = (lower_right_x - upper_left_x) * (lower_right_y - upper_left_y);
+			}
+			else
+			{
 				region = 0;
+			}
 
 			frame_buffer_info.framebuffer_height = lower_right_y;
 			calculate_buffer_size();