Index: uspace/lib/gui/terminal.c
===================================================================
--- uspace/lib/gui/terminal.c	(revision 7dba813edf9ca94fe86972cf728c299ee15088c8)
+++ uspace/lib/gui/terminal.c	(revision c4ebe025c2fab360da14b4704075168c94a51a2c)
@@ -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) {