diff --git a/src/render-fx/bopti.c b/src/render-fx/bopti.c
index c2f83ed..8457aa0 100644
--- a/src/render-fx/bopti.c
+++ b/src/render-fx/bopti.c
@@ -203,7 +203,7 @@ void bopti_render(bopti_image_t const *img, struct rbox *rbox, uint32_t *v1,
 	  .columns      = rbox->columns,
 	  .masks        = masks + 2 * left_origin,
 	  .real_start   = (left_origin > 0),
-	  .real_end     = (rbox->x & 31) && (left_origin + img_columns < 5),
+	  .real_end     = (rbox->x & 31) && (left_origin + rbox->columns < 5),
 	  .vram_stride  = 4 - rbox->columns,
 	  .data_stride  = ((img_columns - rbox->columns) << 2) * layers,
 	  .gray         = (v2 != NULL),