Index: uspace/lib/c/include/io/pixelmap.h
===================================================================
--- uspace/lib/c/include/io/pixelmap.h	(revision 7dba813edf9ca94fe86972cf728c299ee15088c8)
+++ uspace/lib/c/include/io/pixelmap.h	(revision ba733e838a05e6c800b53260e775d067a02d6f27)
@@ -52,7 +52,11 @@
     sysarg_t y)
 {
-	size_t offset = y * pixelmap->width + x;
-	pixel_t *pixel = pixelmap->data + offset;
-	return pixel;
+	if (x < pixelmap->width && y < pixelmap->height) {
+		size_t offset = y * pixelmap->width + x;
+		pixel_t *pixel = pixelmap->data + offset;
+		return pixel;
+	} else {
+		return NULL;
+	}
 }
 
Index: uspace/lib/draw/surface.c
===================================================================
--- uspace/lib/draw/surface.c	(revision 7dba813edf9ca94fe86972cf728c299ee15088c8)
+++ uspace/lib/draw/surface.c	(revision ba733e838a05e6c800b53260e775d067a02d6f27)
@@ -171,16 +171,10 @@
 	surface->dirty_y_hi = surface->dirty_y_hi < y ? y : surface->dirty_y_hi;
 
-	if (x < surface->pixmap.width && y < surface->pixmap.height) {
-		pixelmap_put_pixel(&surface->pixmap, x, y, pixel);
-	}
+	pixelmap_put_pixel(&surface->pixmap, x, y, pixel);
 }
 
 pixel_t surface_get_pixel(surface_t *surface, surface_coord_t x, surface_coord_t y)
 {
-	if (x < surface->pixmap.width && y < surface->pixmap.height) {
-		return pixelmap_get_pixel(&surface->pixmap, x, y);
-	} else {
-		return 0;
-	}
+	return pixelmap_get_pixel(&surface->pixmap, x, y);
 }
 
Index: uspace/lib/gui/terminal.c
===================================================================
--- uspace/lib/gui/terminal.c	(revision 7dba813edf9ca94fe86972cf728c299ee15088c8)
+++ uspace/lib/gui/terminal.c	(revision ba733e838a05e6c800b53260e775d067a02d6f27)
@@ -199,4 +199,7 @@
 		pixel_t *dst = pixelmap_pixel_at(
 		    surface_pixmap_access(surface), bx, by + y);
+		pixel_t *dst_max = pixelmap_pixel_at(
+		    surface_pixmap_access(surface), bx + FONT_WIDTH - 1, by + y);
+		if (!dst || !dst_max) continue;
 		int count = FONT_WIDTH;
 		while (count-- != 0) {