diff --git a/supabase/migrations/20260525200000_room_png_ids.sql b/supabase/migrations/20260525200000_room_png_ids.sql
index 9022523..538c009 100644
--- a/supabase/migrations/20260525200000_room_png_ids.sql
+++ b/supabase/migrations/20260525200000_room_png_ids.sql
@@ -1,7 +1,8 @@
 -- Room backgrounds: PNG assets in /public/room with ids room-1 .. room-4.
 
+-- Drop legacy check before rewriting values (old ids: room-day, room-dusk, etc.).
 alter table public.avatar_state
-  alter column room_background set default 'room-1';
+  drop constraint if exists avatar_state_room_background_check;
 
 update public.avatar_state
 set room_background = case room_background
@@ -22,30 +23,13 @@ where room_background in (
   'room-neon'
 );
 
-update public.user_items
-set item_id = case item_id
-  when 'room-night' then 'room-3'
-  when 'room-forest' then 'room-4'
-  else item_id
-end
-where item_id in ('room-night', 'room-forest');
-
-delete from public.shop_items
-where id in ('room-night', 'room-forest');
-
-insert into public.shop_items (id, name, type, price, image_path)
-values
-  ('room-3', 'Starlit Night', 'room', 40, '/room/room-3.png'),
-  ('room-4', 'Mystic Forest', 'room', 50, '/room/room-4.png')
-on conflict (id) do update
-set
-  name = excluded.name,
-  type = excluded.type,
-  price = excluded.price,
-  image_path = excluded.image_path;
+update public.avatar_state
+set room_background = 'room-1'
+where room_background is null
+  or room_background not in ('room-1', 'room-2', 'room-3', 'room-4');
 
 alter table public.avatar_state
-  drop constraint if exists avatar_state_room_background_check;
+  alter column room_background set default 'room-1';
 
 alter table public.avatar_state
   add constraint avatar_state_room_background_check
@@ -57,3 +41,26 @@ alter table public.avatar_state
       'room-4'
     )
   );
+
+-- New shop rows must exist before user_items FK references are updated.
+insert into public.shop_items (id, name, type, price, image_path)
+values
+  ('room-3', 'Starlit Night', 'room', 40, '/room/room-3.png'),
+  ('room-4', 'Mystic Forest', 'room', 50, '/room/room-4.png')
+on conflict (id) do update
+set
+  name = excluded.name,
+  type = excluded.type,
+  price = excluded.price,
+  image_path = excluded.image_path;
+
+update public.user_items
+set item_id = case item_id
+  when 'room-night' then 'room-3'
+  when 'room-forest' then 'room-4'
+  else item_id
+end
+where item_id in ('room-night', 'room-forest');
+
+delete from public.shop_items
+where id in ('room-night', 'room-forest');