diff --git a/src/Database/LSMTree/Internal/WriteBufferBlobs.hs b/src/Database/LSMTree/Internal/WriteBufferBlobs.hs
index d867ec5a4..8519b37e9 100644
--- a/src/Database/LSMTree/Internal/WriteBufferBlobs.hs
+++ b/src/Database/LSMTree/Internal/WriteBufferBlobs.hs
@@ -170,7 +170,7 @@ addBlob fs WriteBufferBlobs {blobFileName, blobFileState} blob = do
         -- we can also be asked to retrieve blobs at any time.
         blobFileHandle <- FS.hOpen fs blobFileName (FS.ReadWriteMode FS.MustBeNew)
         blobFilePointer <- newFilePointer
-        P.writeMutVar blobFileState OpenBlobFile {
+        P.writeMutVar blobFileState $! OpenBlobFile {
           blobFileHandle,
           blobFilePointer
         }
diff --git a/test/Database/LSMTree/Class/Normal.hs b/test/Database/LSMTree/Class/Normal.hs
index c518350b5..8156b5a7d 100644
--- a/test/Database/LSMTree/Class/Normal.hs
+++ b/test/Database/LSMTree/Class/Normal.hs
@@ -245,14 +245,8 @@ instance IsTableHandle R.TableHandle where
     new = R.new
     close = R.close
     lookups = flip R.lookups
-    -- TODO: This is temporary, because it will otherwise make class tests fail.
-    -- Allow updates with blobs once blob retrieval is implemented.
-    updates th upds = flip R.updates th $ flip V.map upds $ \case
-        (k, R.Insert v _) -> (k, R.Insert v Nothing)
-        upd -> upd
-    -- TODO: This is temporary, because it will otherwise make class tests fail.
-    -- Allow inserts with blobs once blob retrieval is implemented.
-    inserts th ins = flip R.inserts th $ flip V.map ins $ \(k, v, _) -> (k, v, Nothing)
+    updates = flip R.updates
+    inserts = flip R.inserts
     deletes = flip R.deletes
 
     rangeLookup = flip R.rangeLookup
diff --git a/test/Database/LSMTree/Model/Normal/Session.hs b/test/Database/LSMTree/Model/Normal/Session.hs
index 03a1bb37c..e55825067 100644
--- a/test/Database/LSMTree/Model/Normal/Session.hs
+++ b/test/Database/LSMTree/Model/Normal/Session.hs
@@ -440,8 +440,19 @@ snapshot ::
   -> TableHandle k v blob
   -> m ()
 snapshot name th@TableHandle{..} = do
-    table <- snd <$> guardTableHandleIsOpen th
+    (updc, table) <- guardTableHandleIsOpen th
     snaps <- gets snapshots
+    -- TODO: For the moment we allow snapshot to invalidate blob refs.
+    -- Ideally we should change the implementation to not invalidate on
+    -- snapshot, and then we can remove the artificial invalidation from
+    -- the model (i.e. delete the lines below that increments updc).
+    -- Furthermore, we invalidate them _before_ checking if there is a
+    -- duplicate snapshot. This is a bit barmy, but it matches the
+    -- implementation. The implementation should be fixed.
+    -- TODO: See https://github.com/IntersectMBO/lsm-tree/issues/392
+    modify (\m -> m {
+        tableHandles = Map.insert tableHandleID (updc + 1, toSomeTable table) (tableHandles m)
+      })
     when (Map.member name snaps) $
       throwError ErrSnapshotExists
     modify (\m -> m {
diff --git a/test/Test/Database/LSMTree/Class/Normal.hs b/test/Test/Database/LSMTree/Class/Normal.hs
index 8d516d023..81776abed 100644
--- a/test/Test/Database/LSMTree/Class/Normal.hs
+++ b/test/Test/Database/LSMTree/Class/Normal.hs
@@ -59,24 +59,25 @@ tests = testGroup "Test.Database.LSMTree.Class.Normal"
     expectFailures2 = [
         False
       , False
-      , True
       , False
       , False
       , False
-      , True
       , False
-      , True
-      , True
       , False
       , False
       , False
-      , True
-      , False
-      , False
       , False
       , False
       , False
       , False
+      , True
+        --TODO: Blobs are now enabled but cursors do not yet support them
+      , True
+      , True
+      , True
+      , True
+      , True
+      , True
       , False
       , False
       , False
diff --git a/test/Test/Database/LSMTree/Normal/StateMachine.hs b/test/Test/Database/LSMTree/Normal/StateMachine.hs
index 52fa3f8bd..8edf91214 100644
--- a/test/Test/Database/LSMTree/Normal/StateMachine.hs
+++ b/test/Test/Database/LSMTree/Normal/StateMachine.hs
@@ -197,6 +197,7 @@ propLockstepIO_RealImpl_RealFS = testProperty "propLockstepIO_RealImpl_RealFS" $
         handler' (ErrSnapshotNotExists _snap) = Just Model.ErrSnapshotDoesNotExist
         handler' (ErrSnapshotExists _snap) = Just Model.ErrSnapshotExists
         handler' (ErrSnapshotWrongType _snap) = Just Model.ErrSnapshotWrongType
+        handler' (ErrBlobRefInvalid _) = Just Model.ErrBlobRefInvalidated
         handler' _ = Nothing
 
 {- TODO: temporarily disabled until we start on I/O fault testing.
@@ -520,7 +521,7 @@ instance ( Eq (Class.TableConfig h)
       MLookupResult x      -> OLookupResult $ fmap observeModel x
       MQueryResult x       -> OQueryResult $ fmap observeModel x
       MSnapshotName x      -> OId x
-      MBlob x              -> OId x
+      MBlob x              -> OBlob x
       MErr x               -> OId x
       MUnit x              -> OId x
       MPair x              -> OPair $ bimap observeModel observeModel x
@@ -591,8 +592,9 @@ instance Eq (Obs h a) where
       -- blob reference immediately after an update to the table, and if the SUT
       -- returns a blob, then that's okay. If both return a blob or both return
       -- an error, then those must match exactly.
-      (OEither (Right (OBlob (WrapBlob _))), OEither (Left (OId y)))
-        | Just Model.ErrBlobRefInvalidated <- cast y -> True
+      (OEither (Right (OVector vec)), OEither (Left (OId y)))
+        | Just (OBlob (WrapBlob _), _) <- V.uncons vec
+        , Just Model.ErrBlobRefInvalidated <- cast y -> True
       -- default equalities
       (OTableHandle, OTableHandle) -> True
       (OCursor, OCursor) -> True
@@ -664,7 +666,7 @@ instance ( Eq (Class.TableConfig h)
       Updates{}        -> OEither $ bimap OId OId result
       Inserts{}        -> OEither $ bimap OId OId result
       Deletes{}        -> OEither $ bimap OId OId result
-      RetrieveBlobs{}  -> OEither $ bimap OId (OVector . fmap OId) result
+      RetrieveBlobs{}  -> OEither $ bimap OId (OVector . fmap OBlob) result
       Snapshot{}       -> OEither $ bimap OId OId result
       Open{}           -> OEither $ bimap OId (const OTableHandle) result
       DeleteSnapshot{} -> OEither $ bimap OId OId result
@@ -1041,9 +1043,8 @@ arbitraryActionWithVars _ findVars _st = QC.frequency $ concat [
     withVars'' ::
          Gen (Var h (Either Model.Err (V.Vector (WrapBlobRef h IO blob))))
       -> [(Int, Gen (Any (LockstepAction (ModelState h))))]
-    withVars'' _genBlobRefsVar = [
-          -- TODO: enable generators as we implement the actions for the /real/ lsm-tree
-          -- fmap Some $ RetrieveBlobs <$> (fromRight <$> genBlobRefsVar)
+    withVars'' genBlobRefsVar = [
+          (5, fmap Some $ RetrieveBlobs <$> (fromRight <$> genBlobRefsVar))
         ]
 
     fromRight ::
@@ -1082,9 +1083,10 @@ arbitraryActionWithVars _ findVars _st = QC.frequency $ concat [
     genDeletes :: Gen (V.Vector k)
     genDeletes = QC.arbitrary
 
-    -- TODO: generate @Just blob@ once blob references are implemented
     genBlob :: Gen (Maybe blob)
-    genBlob = Nothing <$ QC.arbitrary @blob
+    genBlob = QC.oneof [ pure Nothing
+                       , Just <$> QC.arbitrary @blob
+                       ]
 
     genSnapshotName :: Gen R.SnapshotName
     genSnapshotName = QC.elements [