diff --git a/src/renderer.ml b/src/renderer.ml
index 4059544..c9ecebd 100644
--- a/src/renderer.ml
+++ b/src/renderer.ml
@@ -97,11 +97,14 @@ let add_box render_data range opt_data : render_data_t * int =
 
 (** Same as [add_box], with an included start, excluded end for range. *)
 let add_box_excl render_data (addr_beg, addr_end) opt_data =
-  (match RawAsm.AddrMap.find_opt addr_end render_data.render_prev_address with
-   | None -> Format.eprintf "Box end address %x not found, ignoring box."
-               addr_end ;
-            raise Not_found
-   | Some end_bound -> add_box render_data (addr_beg, end_bound) opt_data
+  let lower_than_end addr = addr <= addr_end in
+  (match RawAsm.AddrMap.find_last_opt
+           lower_than_end render_data.render_prev_address with
+  | None ->
+    Format.eprintf "Box end address %x not found, ignoring box.@."
+      addr_end ;
+    raise Not_found
+  | Some (_, end_bound) -> add_box render_data (addr_beg, end_bound) opt_data
   )
 
 (** [to_file renderer render_data path] renders the given [render_data] to a