diff --git a/include/pokemon.h b/include/pokemon.h
index f4f6d6989..6d08f4874 100644
--- a/include/pokemon.h
+++ b/include/pokemon.h
@@ -202,7 +202,8 @@ struct BoxPokemon
     u8 isBadEgg:1;
     u8 hasSpecies:1;
     u8 isEgg:1;
-    u8 unused:5;
+    u8 blockBoxRS:1; // Unused, but Pokémon Box Ruby & Sapphire will refuse to deposit a Pokémon with this flag set
+    u8 unused:4;
     u8 otName[PLAYER_NAME_LENGTH];
     u8 markings;
     u16 checksum;