diff --git a/src/driver/framebuffer_spark.cpp b/src/driver/framebuffer_spark.cpp
index 6493f1327..113daccd6 100644
--- a/src/driver/framebuffer_spark.cpp
+++ b/src/driver/framebuffer_spark.cpp
@@ -932,6 +932,8 @@ _display:
 
 	if (paintBg)
 		paintBoxRel(x, yy, width, height, colBg);
+	/* to make sure backbuffer is already blitted completely... */
+	waitForIdle();
 	blit2FB(data, width, height, x, yy, 0, 0, true);
 	return true;
 }