diff --git a/source/arm11/atp.c b/source/arm11/atp.c
index 2e7258f..555ccce 100644
--- a/source/arm11/atp.c
+++ b/source/arm11/atp.c
@@ -88,7 +88,7 @@ static void screen_clean_zone( int x, int y, int w, int h )
     if( x < 0 || y < 0 || x+w >= WINDOW_WIDTH || y+h >=WINDOW_HEIGHT )
         return;
     
-    for( int i=0; i < w; i++ ) memset( consoleGet()->frameBuffer + WINDOW_HEIGHT*(i+x) + (WINDOW_HEIGHT-1-y-h), 0, h );
+    for( int i=0; i < w; i++ ) memset( consoleGet()->frameBuffer + WINDOW_HEIGHT*(i+x) + (WINDOW_HEIGHT-1-y-h), 0xff, h*sizeof(u16) );
 }
 
 // wait key pressed, if power key is pressed, return 0