diff --git a/apps/rooms/src/openapi.ts b/apps/rooms/src/openapi.ts
index 4290f93..08b4311 100644
--- a/apps/rooms/src/openapi.ts
+++ b/apps/rooms/src/openapi.ts
@@ -255,7 +255,10 @@ export const SubRoomDto = z.object({
 		'The latest room save — where the client finds the scene blob. Null until first save'
 	),
 	DataBlob: z.string().optional().describe('Legacy flat key; the client reads `CurrentSave`'),
-	RoomDataBlob: z.string().optional().describe('Uploaded room-data key; absent until first save'),
+	RoomDataBlob: z
+		.string()
+		.optional()
+		.describe('Legacy; the room-level blob is the ROOM’s `DataBlob`. Not a key the client knows'),
 	DataSavedAt: z.string().optional().describe('ISO timestamp of the last save'),
 	PersistenceVersion: z.int().optional(),
 	InventionUsage: z.string().optional().describe('Recorded by a room save; absent until then'),
@@ -304,6 +307,11 @@ export const RoomDto = z.object({
 	PublishedAt: z.string(),
 	BecameRRStudioRoomAt: z.string().nullable(),
 	Stats: RoomStatsDto,
+	DataBlob: z
+		.string()
+		.optional()
+		.describe('The room-level metadata blob a room save uploads as `RoomData`; absent until one'),
+	DataBlobHash: z.string().nullable().optional().describe('`RoomData.Hash` from that save'),
 	BoostCount: z
 		.int()
 		.describe('Boosts on the room. Nothing grants boosts here, so always 0 — but present'),
@@ -877,9 +885,11 @@ export const SaveSubRoomDataRequest = z.object({
 		.optional()
 		.describe('The uploaded scene-data blob — becomes the subroom’s `CurrentSave.DataBlob`'),
 	RoomData: z
-		.object({ Filename: z.string() })
+		.object({ Filename: z.string(), Hash: z.string().nullable().optional() })
 		.optional()
-		.describe('The uploaded room-level data blob — becomes `RoomDataBlob`'),
+		.describe(
+			'The uploaded room-level metadata blob — becomes the ROOM’s `DataBlob`/`DataBlobHash`'
+		),
 	Description: z
 		.string()
 		.optional()
diff --git a/apps/rooms/src/rooms.app.ts b/apps/rooms/src/rooms.app.ts
index 2beed05..b7228c7 100644
--- a/apps/rooms/src/rooms.app.ts
+++ b/apps/rooms/src/rooms.app.ts
@@ -3606,10 +3606,11 @@ const app = new Hono<App>()
 			if (!canManageRoom(room, accountId)) return c.body(null, 403)
 
 			// The client uploads BOTH blobs to `storage` first and sends their keys here:
-			// `SubRoomData` is the scene blob (what the loader downloads), `RoomData` the
-			// metadata blob. `OwnershipProof` is accepted and ignored.
+			// `SubRoomData` is the scene blob (what the loader downloads, onto the subroom's
+			// save), `RoomData` the room-level metadata blob (onto the ROOM, as `DataBlob`).
+			// `OwnershipProof` is accepted and ignored.
 			const body = (await c.req.json().catch(() => ({}))) as {
-				RoomData?: { Filename?: string }
+				RoomData?: { Filename?: string; Hash?: string | null }
 				SubRoomData?: { Filename?: string; Hash?: string | null }
 				UnityAssetId?: string | null
 				Description?: string
@@ -3623,6 +3624,7 @@ const app = new Hono<App>()
 				subRoomDataHash:
 					typeof body.SubRoomData?.Hash === 'string' ? body.SubRoomData.Hash : undefined,
 				roomDataFilename: body.RoomData?.Filename,
+				roomDataHash: typeof body.RoomData?.Hash === 'string' ? body.RoomData.Hash : undefined,
 				unityAssetId: typeof body.UnityAssetId === 'string' ? body.UnityAssetId : undefined,
 				autoPublish: body.AutoPublish === true,
 				description: typeof body.Description === 'string' ? body.Description : undefined,
diff --git a/apps/rooms/src/test/integration/api.test.ts b/apps/rooms/src/test/integration/api.test.ts
index 3249dcd..d7dd821 100644
--- a/apps/rooms/src/test/integration/api.test.ts
+++ b/apps/rooms/src/test/integration/api.test.ts
@@ -3552,10 +3552,20 @@ describe('rooms endpoints', () => {
 			(s) => s.SubRoomId === 2
 		)!
 		expect(savedSub).toMatchObject({
-			RoomDataBlob: '5c618c920f6247efb8327e327d0b4417',
 			CreatorAccountId: 1,
 			PersistenceVersion: 41,
 		})
+		// `RoomData` is the ROOM-level metadata blob: it lands on the room as `DataBlob`, which
+		// is where the client reads it — not on the subroom, which has no field for it.
+		expect(savedSub).not.toHaveProperty('RoomDataBlob')
+		expect(saved.value.room).toMatchObject({
+			DataBlob: '5c618c920f6247efb8327e327d0b4417',
+			DataBlobHash: null,
+		})
+		expect(await (await SELF.fetch(`${ORIGIN}/rooms/2`)).json()).toMatchObject({
+			DataBlob: '5c618c920f6247efb8327e327d0b4417',
+			DataBlobHash: null,
+		})
 		expect(savedSub.CurrentSave).toMatchObject({
 			DataBlob: 'a84167b16796452ab70ee8a6a5b1dc5f',
 		})
diff --git a/apps/storage/src/storage.app.ts b/apps/storage/src/storage.app.ts
index 31d6b41..883c661 100644
--- a/apps/storage/src/storage.app.ts
+++ b/apps/storage/src/storage.app.ts
@@ -37,7 +37,12 @@ import type { App } from './context'
  *
  * RoomSave (1) lands under `room/` (not `roomsave/`) so the `cdn` worker's
  * `GET /room/:dataBlob` route serves the blob back — both bind the same
- * `recflare-cdn` bucket, so the key prefixes must match.
+ * `recflare-cdn` bucket, so the key prefixes must match. RoomMetadata (6) — the
+ * room-level blob a room save posts as `RoomData`, which the room then names as its
+ * `DataBlob` — lands under `room/` too: the client fetches it from the same
+ * `/room/<name>` path it fetches the scene from. It once went under `roommetadata/`,
+ * where nothing ever asked for it. The two never collide — every upload is named by
+ * a fresh GUID under the day's folder.
  */
 const UPLOAD_SUBFOLDER: Record<number, string> = {
 	1: 'room',
@@ -45,7 +50,7 @@ const UPLOAD_SUBFOLDER: Record<number, string> = {
 	3: 'image',
 	4: 'video',
 	5: 'invention',
-	6: 'roommetadata',
+	6: 'room',
 }
 
 /** Resolve the storage subfolder for a posted FileType, or `undefined` when unknown. */
diff --git a/apps/storage/src/test/integration/api.test.ts b/apps/storage/src/test/integration/api.test.ts
index c7e5331..cf3fe66 100644
--- a/apps/storage/src/test/integration/api.test.ts
+++ b/apps/storage/src/test/integration/api.test.ts
@@ -63,7 +63,7 @@ it('POST /upload 401s without a token', async () => {
 	expect(res.status).toBe(401)
 })
 
-it('POST /upload stores a RoomMetadata (FileType 6) file under roommetadata/ and returns its name', async () => {
+it('POST /upload stores a RoomMetadata (FileType 6) file under room/ and returns its name', async () => {
 	// Mirrors the client's multipart upload: FileType=6, File=<binary>.
 	const bytes = new Uint8Array([0x10, 0x02, 0x1a, 0x00])
 	const res = await SELF.fetch(`${ORIGIN}/upload`, {
@@ -77,8 +77,9 @@ it('POST /upload stores a RoomMetadata (FileType 6) file under roommetadata/ and
 		/^\d{4}-\d{2}-\d{2}\/[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}$/
 	)
 
-	// The bytes are persisted in the shared CDN bucket under the type subfolder.
-	const stored = await env.CDN_ASSETS.get(`roommetadata/${filename}`)
+	// The bytes are persisted in the shared CDN bucket under `room/`, the same folder as a
+	// scene blob: the client downloads the room's `DataBlob` from the cdn's `/room/<name>`.
+	const stored = await env.CDN_ASSETS.get(`room/${filename}`)
 	expect(stored).not.toBeNull()
 	expect(new Uint8Array(await stored!.arrayBuffer())).toEqual(bytes)
 })
diff --git a/packages/domain/src/rooms-db.ts b/packages/domain/src/rooms-db.ts
index fd9be60..e430a5e 100644
--- a/packages/domain/src/rooms-db.ts
+++ b/packages/domain/src/rooms-db.ts
@@ -1310,8 +1310,15 @@ export interface SaveSubRoomDataInput {
 	subRoomDataFilename?: string
 	/** `SubRoomData.Hash` — echoed back as the save response's `dataBlobHash`. */
 	subRoomDataHash?: string
-	/** Uploaded blob key for the room-level METADATA blob (a separate upload). */
+	/**
+	 * `RoomData.Filename` — the uploaded ROOM-level metadata blob (a separate upload from the
+	 * scene). It lands on the ROOM as `DataBlob`, not on the subroom: the client's `Room` has
+	 * `DataBlob`/`DataBlobHash` and its `SubRoom` has no field for it (`RoomDataBlob`, where
+	 * this once went, is not a key the client knows, and it dropped it silently).
+	 */
 	roomDataFilename?: string
+	/** `RoomData.Hash` — stored beside it as the room's `DataBlobHash`; null when unsent. */
+	roomDataHash?: string
 	/**
 	 * The save comment — a description of THIS revision, typed into the client's save box.
 	 * It belongs to the save (and shows up in the `…/saves` history); it is not the room's
@@ -1643,18 +1650,35 @@ export async function saveSubRoomData(
 		})
 	)
 	const saveId = Number(save.SubRoomDataSaveId)
-	if (input.roomDataFilename) sub.RoomDataBlob = input.roomDataFilename
 	sub.DataSavedAt = new Date().toISOString()
 	if (input.persistenceVersion !== undefined) sub.PersistenceVersion = input.persistenceVersion
 	if (input.inventionUsage !== undefined) sub.InventionUsage = input.inventionUsage
 
-	// Nothing here touches the ROOM. A room save is a revision of one SUBROOM, and every
-	// field it carries describes that revision: `Description` is the save comment shown in
-	// the `…/saves` history, `PersistenceVersion` and `InventionUsage` describe the scene
-	// just saved. They used to be copied onto the room as well, which meant each save
-	// silently replaced the room's public description with the save comment. The room's own
-	// fields are edited through their own routes (`PUT /rooms/:id/description` and
-	// friends), so the room row is not rewritten here at all.
+	// The ONE thing a save writes on the ROOM: `RoomData`, the room-level metadata blob the
+	// client uploads beside the scene. The client's `Room` reads it as `DataBlob` (with
+	// `DataBlobHash`), so that is where it goes — a targeted `json_set` of those two keys,
+	// never a rewrite of the room row. It used to be put on the subroom as `RoomDataBlob`,
+	// which the client has no field for, so no save ever reached it.
+	//
+	// Everything else the save carries describes the SUBROOM's revision: `Description` is the
+	// save comment shown in the `…/saves` history, `PersistenceVersion` and `InventionUsage`
+	// describe the scene just saved. They used to be copied onto the room as well, which
+	// meant each save silently replaced the room's public description with the save comment.
+	// The room's own fields are edited through their own routes (`PUT /rooms/:id/description`
+	// and friends).
+	const roomWrites: D1PreparedStatement[] = []
+	if (input.roomDataFilename) {
+		const hash = input.roomDataHash ?? null
+		room.DataBlob = input.roomDataFilename
+		room.DataBlobHash = hash
+		roomWrites.push(
+			db
+				.prepare(
+					"UPDATE room SET data = json_set(data, '$.DataBlob', ?2, '$.DataBlobHash', ?3) WHERE room_id = ?1"
+				)
+				.bind(roomId, input.roomDataFilename, hash)
+		)
+	}
 
 	// Publish outright when the client asked to (`AutoPublish`), or for a dorm — a dorm is
 	// the player's own private space with no publish step in the client, so staging one
@@ -1662,6 +1686,7 @@ export async function saveSubRoomData(
 	// `publish_save`. One round trip for the rest of the save.
 	const publishNow = input.autoPublish === true || room.IsDorm === true
 	await db.batch([
+		...roomWrites,
 		publishNow
 			? db
 					.prepare(