diff --git a/src/devices/screen.c b/src/devices/screen.c
index 5f239de..f61b318 100644
--- a/src/devices/screen.c
+++ b/src/devices/screen.c
@@ -53,6 +53,14 @@ screen_blit(UxnScreen *p, Layer *layer, Uint16 x, Uint16 y, Uint8 *sprite, Uint8
 	}
 }
 
+static void layer_clear(UxnScreen *p, Layer *layer)
+{
+	Uint32 i, size = p->width * p->height;
+	for(i = 0; i < size; i++)
+		layer->pixels[i] = 0x00;
+	layer->changed = 1;
+}
+
 void
 screen_palette(UxnScreen *p, Uint8 *addr)
 {
@@ -82,18 +90,15 @@ screen_resize(UxnScreen *p, Uint16 width, Uint16 height)
 	if(bg && fg && pixels) {
 		p->width = width;
 		p->height = height;
-		screen_clear(p, &p->bg);
-		screen_clear(p, &p->fg);
+		screen_clear(p);
 	}
 }
 
 void
-screen_clear(UxnScreen *p, Layer *layer)
+screen_clear(UxnScreen *p)
 {
-	Uint32 i, size = p->width * p->height;
-	for(i = 0; i < size; i++)
-		layer->pixels[i] = 0x00;
-	layer->changed = 1;
+	layer_clear(p, &p->bg);
+	layer_clear(p, &p->fg);
 }
 
 void
diff --git a/src/devices/screen.h b/src/devices/screen.h
index 011cafe..cbe051a 100644
--- a/src/devices/screen.h
+++ b/src/devices/screen.h
@@ -25,7 +25,7 @@ extern UxnScreen uxn_screen;
 
 void screen_palette(UxnScreen *p, Uint8 *addr);
 void screen_resize(UxnScreen *p, Uint16 width, Uint16 height);
-void screen_clear(UxnScreen *p, Layer *layer);
+void screen_clear(UxnScreen *p);
 void screen_redraw(UxnScreen *p, Uint32 *pixels);
 
 Uint8 screen_dei(Uint8 *d, Uint8 port);
diff --git a/src/devices/system.c b/src/devices/system.c
index f9a83a4..c6f44ba 100644
--- a/src/devices/system.c
+++ b/src/devices/system.c
@@ -17,8 +17,7 @@ WITH REGARD TO THIS SOFTWARE.
 static const char *errors[] = {
 	"underflow",
 	"overflow",
-	"division by zero"
-};
+	"division by zero"};
 
 static void
 system_print(Stack *s, char *name)
diff --git a/src/uxn11.c b/src/uxn11.c
index c3ac56a..93d9142 100644
--- a/src/uxn11.c
+++ b/src/uxn11.c
@@ -105,7 +105,9 @@ emu_start(Uxn *u, char *rom)
 {
 	if(!load_rom(u, rom))
 		return 0;
-	screen_resize(&uxn_screen, WIDTH, HEIGHT);
+	if(!uxn_screen.width || !uxn_screen.height)
+		screen_resize(&uxn_screen, WIDTH, HEIGHT);
+	screen_clear(&uxn_screen);
 	if(!uxn_eval(u, PAGE_PROGRAM))
 		return emu_error("Boot", "Failed to start rom.");
 	return 1;