diff --git a/src/reskit/level/system.rs b/src/reskit/level/system.rs
index 28acfa5..70e91bb 100644
--- a/src/reskit/level/system.rs
+++ b/src/reskit/level/system.rs
@@ -379,6 +379,14 @@ pub fn get_ecs( tilemap: &TiledTilemap ) -> Result<Vec<u8>, Box<dyn Error>> {
         }
     }
 
+    // Fill the remainder of the sparse array with 0xFF, if needed
+    let remainder = 512 - tilemap.ecs.len();
+    for _ in 0..remainder {
+        for _ in 0..largest_type_attributes_size {
+            result.extend( ( 0xFFFF as u16 ).to_be_bytes() );
+        }
+    }
+
     // Output IDs to terminal
     let component_ids: Vec<String> = component_ids.into_iter().collect();
     for i in 0..component_ids.len() {