diff --git a/litestream/api.go b/litestream/api.go
index 1608c91..e61bd76 100644
--- a/litestream/api.go
+++ b/litestream/api.go
@@ -59,19 +59,19 @@ func NewReplica(name string, client ReplicaClient, options ReplicaOptions) {
 	}
 
 	liteMtx.Lock()
-	defer liteMtx.Unlock()
 	liteDBs[name] = &liteDB{
 		client: client,
 		opts:   options,
 		cache:  pageCache{size: options.CacheSize},
 	}
+	liteMtx.Unlock()
 }
 
 // RemoveReplica removes a replica by name.
 func RemoveReplica(name string) {
 	liteMtx.Lock()
-	defer liteMtx.Unlock()
 	delete(liteDBs, name)
+	liteMtx.Unlock()
 }
 
 type ReplicaClient = litestream.ReplicaClient
diff --git a/litestream/go.mod b/litestream/go.mod
index cada5b8..3611251 100644
--- a/litestream/go.mod
+++ b/litestream/go.mod
@@ -4,7 +4,7 @@ go 1.24.4
 
 require (
 	github.com/benbjohnson/litestream v0.5.5
-	github.com/ncruces/go-sqlite3 v0.30.4-0.20251216123455-0b46e74ea69b
+	github.com/ncruces/go-sqlite3 v0.30.4
 	github.com/ncruces/wbt v0.2.0
 	github.com/superfly/ltx v0.5.1
 )
diff --git a/litestream/go.sum b/litestream/go.sum
index c5adc0a..19679ae 100644
--- a/litestream/go.sum
+++ b/litestream/go.sum
@@ -105,8 +105,8 @@ github.com/nats-io/nkeys v0.4.11 h1:q44qGV008kYd9W1b1nEBkNzvnWxtRSQ7A8BoqRrcfa0=
 github.com/nats-io/nkeys v0.4.11/go.mod h1:szDimtgmfOi9n25JpfIdGw12tZFYXqhGxjhVxsatHVE=
 github.com/nats-io/nuid v1.0.1 h1:5iA8DT8V7q8WK2EScv2padNa/rTESc1KdnPw4TC2paw=
 github.com/nats-io/nuid v1.0.1/go.mod h1:19wcPz3Ph3q0Jbyiqsd0kePYG7A95tJPxeL+1OSON2c=
-github.com/ncruces/go-sqlite3 v0.30.4-0.20251216123455-0b46e74ea69b h1:0HG7ul3Q1d/E/jrZpBTpzx4xhxJwMKuq5J4nuZIogm8=
-github.com/ncruces/go-sqlite3 v0.30.4-0.20251216123455-0b46e74ea69b/go.mod h1:wz6IQnveXfqaXZozfhM8ciIJi2LRnnifBuBQarPDYo0=
+github.com/ncruces/go-sqlite3 v0.30.4 h1:j9hEoOL7f9ZoXl8uqXVniaq1VNwlWAXihZbTvhqPPjA=
+github.com/ncruces/go-sqlite3 v0.30.4/go.mod h1:7WR20VSC5IZusKhUdiR9y1NsUqnZgqIYCmKKoMEYg68=
 github.com/ncruces/julianday v1.0.0 h1:fH0OKwa7NWvniGQtxdJRxAgkBMolni2BjDHaWTxqt7M=
 github.com/ncruces/julianday v1.0.0/go.mod h1:Dusn2KvZrrovOMJuOt0TNXL6tB7U2E8kvza5fFc9G7g=
 github.com/ncruces/litestream v0.5.5 h1:LUoyorC+Xx0TtiuEjwd0+GIusCK5IIZwTPsO1+se55g=
diff --git a/litestream/vfs.go b/litestream/vfs.go
index 1d12742..74c6db0 100644
--- a/litestream/vfs.go
+++ b/litestream/vfs.go
@@ -3,7 +3,6 @@ package litestream
 import (
 	"context"
 	"encoding/binary"
-	"errors"
 	"fmt"
 	"io"
 	"strconv"
@@ -15,7 +14,6 @@ import (
 	"github.com/superfly/ltx"
 
 	"github.com/ncruces/go-sqlite3"
-	"github.com/ncruces/go-sqlite3/util/vfsutil"
 	"github.com/ncruces/go-sqlite3/vfs"
 	"github.com/ncruces/wbt"
 )
@@ -23,9 +21,9 @@ import (
 type liteVFS struct{}
 
 func (liteVFS) Open(name string, flags vfs.OpenFlag) (vfs.File, vfs.OpenFlag, error) {
-	// Temp journals, as used by the sorter, use SliceFile.
+	// Temp journals, as used by the sorter, use a temporary file.
 	if flags&vfs.OPEN_TEMP_JOURNAL != 0 {
-		return &vfsutil.SliceFile{}, flags | vfs.OPEN_MEMORY, nil
+		return vfs.Find("").Open(name, flags)
 	}
 	// Refuse to open all other file types.
 	if flags&vfs.OPEN_MAIN_DB == 0 {
@@ -33,16 +31,19 @@ func (liteVFS) Open(name string, flags vfs.OpenFlag) (vfs.File, vfs.OpenFlag, er
 	}
 
 	liteMtx.RLock()
-	defer liteMtx.RUnlock()
-	if db, ok := liteDBs[name]; ok {
-		// Build the page index so we can lookup individual pages.
-		if err := db.buildIndex(context.Background()); err != nil {
-			db.opts.Logger.Error("build index", "error", err)
-			return nil, 0, err
-		}
-		return &liteFile{db: db}, flags | vfs.OPEN_READONLY, nil
+	db := liteDBs[name]
+	liteMtx.RUnlock()
+
+	if db == nil {
+		return nil, flags, sqlite3.CANTOPEN
 	}
-	return nil, flags, sqlite3.CANTOPEN
+
+	// Build the page index so we can lookup individual pages.
+	if err := db.buildIndex(context.Background()); err != nil {
+		db.opts.Logger.Error("build index", "error", err)
+		return nil, 0, err
+	}
+	return &liteFile{db: db}, flags | vfs.OPEN_READONLY, nil
 }
 
 func (liteVFS) Delete(name string, dirSync bool) error {
@@ -253,17 +254,21 @@ func (f *liteFile) context() context.Context {
 func (f *liteFile) buildIndex(ctx context.Context, syncTime time.Time) error {
 	// Build the index from scratch from a Litestream restore plan.
 	infos, err := litestream.CalcRestorePlan(ctx, f.db.client, 0, syncTime, f.db.opts.Logger)
-	if err != nil && !errors.Is(err, litestream.ErrTxNotAvailable) {
+	if err != nil {
 		return fmt.Errorf("calc restore plan: %w", err)
 	}
 
 	var txid ltx.TXID
 	var pages *pageIndex
+	syncTime = time.Time{}
 	for _, info := range infos {
 		pages, err = fetchPageIndex(ctx, pages, f.db.client, info)
 		if err != nil {
 			return err
 		}
+		if syncTime.Before(info.CreatedAt) {
+			syncTime = info.CreatedAt
+		}
 		txid = max(txid, info.MaxTXID)
 	}
 	f.syncTime = syncTime
@@ -294,7 +299,7 @@ func (d *liteDB) buildIndex(ctx context.Context) error {
 
 	// Build the index from scratch from a Litestream restore plan.
 	infos, err := litestream.CalcRestorePlan(ctx, d.client, 0, time.Time{}, d.opts.Logger)
-	if err != nil && !errors.Is(err, litestream.ErrTxNotAvailable) {
+	if err != nil {
 		return fmt.Errorf("calc restore plan: %w", err)
 	}
 
diff --git a/litestream/vfs_test.go b/litestream/vfs_test.go
index 1a47a7e..abb46d8 100644
--- a/litestream/vfs_test.go
+++ b/litestream/vfs_test.go
@@ -90,35 +90,6 @@ func Test_integration(t *testing.T) {
 	if txid != "0000000000000001" {
 		t.Errorf("got %q", txid)
 	}
-
-	_, err = replica.ExecContext(t.Context(), `PRAGMA litestream_time='-1.5h'`)
-	if err != nil {
-		t.Fatal(err)
-	}
-
-	_, err = replica.ExecContext(t.Context(), `PRAGMA litestream_time='-00:01'`)
-	if err != nil {
-		t.Fatal(err)
-	}
-
-	_, err = replica.ExecContext(t.Context(), `PRAGMA litestream_time='-2.5 years'`)
-	if err != nil {
-		t.Fatal(err)
-	}
-
-	_, err = replica.ExecContext(t.Context(), `PRAGMA litestream_time='1970-01-01'`)
-	if err != nil {
-		t.Fatal(err)
-	}
-
-	var sync time.Time
-	err = replica.QueryRowContext(t.Context(), `PRAGMA litestream_time`).Scan(&sync)
-	if err != nil {
-		t.Fatal(err)
-	}
-	if !sync.Equal(time.Unix(0, 0)) {
-		t.Errorf("got %v", sync)
-	}
 }
 
 func setupReplication(tb testing.TB, path string, client ReplicaClient) {
diff --git a/registry.go b/registry.go
index 043d69e..4376f67 100644
--- a/registry.go
+++ b/registry.go
@@ -14,8 +14,8 @@ var (
 // https://sqlite.org/c3ref/auto_extension.html
 func AutoExtension(entryPoint func(*Conn) error) {
 	extRegistryMtx.Lock()
-	defer extRegistryMtx.Unlock()
 	extRegistry = append(extRegistry, entryPoint)
+	extRegistryMtx.Unlock()
 }
 
 func initExtensions(c *Conn) error {
diff --git a/vfs/memdb/api.go b/vfs/memdb/api.go
index a128198..5a51272 100644
--- a/vfs/memdb/api.go
+++ b/vfs/memdb/api.go
@@ -34,9 +34,6 @@ var (
 // The new database takes ownership of data,
 // and the caller should not use data after this call.
 func Create(name string, data []byte) {
-	memoryMtx.Lock()
-	defer memoryMtx.Unlock()
-
 	db := &memDB{
 		refs: 1,
 		name: name,
@@ -63,14 +60,16 @@ func Create(name string, data []byte) {
 		}
 	}
 
+	memoryMtx.Lock()
 	memoryDBs[name] = db
+	memoryMtx.Unlock()
 }
 
 // Delete deletes a shared memory database.
 func Delete(name string) {
 	memoryMtx.Lock()
-	defer memoryMtx.Unlock()
 	delete(memoryDBs, name)
+	memoryMtx.Unlock()
 }
 
 // TestDB creates an empty shared memory database for the test to use.
diff --git a/vfs/memdb/memdb.go b/vfs/memdb/memdb.go
index eb05059..125f54c 100644
--- a/vfs/memdb/memdb.go
+++ b/vfs/memdb/memdb.go
@@ -92,10 +92,10 @@ type memDB struct {
 
 func (m *memDB) release() {
 	memoryMtx.Lock()
-	defer memoryMtx.Unlock()
 	if m.refs--; m.refs == 0 && m == memoryDBs[m.name] {
 		delete(memoryDBs, m.name)
 	}
+	memoryMtx.Unlock()
 }
 
 type memFile struct {
diff --git a/vfs/mvcc/api.go b/vfs/mvcc/api.go
index 5f20e53..3809e81 100644
--- a/vfs/mvcc/api.go
+++ b/vfs/mvcc/api.go
@@ -35,13 +35,12 @@ var (
 // using a snapshot as its initial contents.
 func Create(name string, snapshot Snapshot) {
 	memoryMtx.Lock()
-	defer memoryMtx.Unlock()
-
 	memoryDBs[name] = &mvccDB{
 		refs: 1,
 		name: name,
 		data: snapshot.Tree,
 	}
+	memoryMtx.Unlock()
 }
 
 // Delete deletes a shared memory database.
@@ -49,8 +48,8 @@ func Delete(name string) {
 	name = getName(name)
 
 	memoryMtx.Lock()
-	defer memoryMtx.Unlock()
 	delete(memoryDBs, name)
+	memoryMtx.Unlock()
 }
 
 // Snapshot represents a database snapshot.
@@ -83,8 +82,9 @@ func TakeSnapshot(name string) Snapshot {
 	name = getName(name)
 
 	memoryMtx.Lock()
-	defer memoryMtx.Unlock()
 	db := memoryDBs[name]
+	memoryMtx.Unlock()
+
 	if db == nil {
 		return Snapshot{}
 	}
diff --git a/vfs/mvcc/mvcc.go b/vfs/mvcc/mvcc.go
index 7e6880f..87437c3 100644
--- a/vfs/mvcc/mvcc.go
+++ b/vfs/mvcc/mvcc.go
@@ -79,10 +79,10 @@ type mvccDB struct {
 
 func (m *mvccDB) release() {
 	memoryMtx.Lock()
-	defer memoryMtx.Unlock()
 	if m.refs--; m.refs == 0 && m == memoryDBs[m.name] {
 		delete(memoryDBs, m.name)
 	}
+	memoryMtx.Unlock()
 }
 
 type mvccFile struct {
@@ -105,10 +105,10 @@ func (m *mvccFile) Close() error {
 	m.data = nil
 	m.lock = vfs.LOCK_NONE
 	m.mtx.Lock()
-	defer m.mtx.Unlock()
 	if m.owner == m {
 		m.owner = nil
 	}
+	m.mtx.Unlock()
 	return nil
 }
 
@@ -313,10 +313,10 @@ func (m *mvccFile) CommitPhaseTwo() error {
 	// Modified without lock, commit changes.
 	if m.lock > vfs.LOCK_EXCLUSIVE {
 		m.mtx.Lock()
-		defer m.mtx.Unlock()
 		m.mvccDB.data = m.data
 		m.lock = vfs.LOCK_NONE
 		m.data = nil
+		m.mtx.Unlock()
 	}
 	return nil
 }
diff --git a/vfs/readervfs/api.go b/vfs/readervfs/api.go
index 60813e7..fd5852e 100644
--- a/vfs/readervfs/api.go
+++ b/vfs/readervfs/api.go
@@ -30,13 +30,13 @@ var (
 // otherwise SQLite might return incorrect query results and/or [sqlite3.CORRUPT] errors.
 func Create(name string, reader ioutil.SizeReaderAt) {
 	readerMtx.Lock()
-	defer readerMtx.Unlock()
 	readerDBs[name] = reader
+	readerMtx.Unlock()
 }
 
 // Delete deletes a shared memory database.
 func Delete(name string) {
 	readerMtx.Lock()
-	defer readerMtx.Unlock()
 	delete(readerDBs, name)
+	readerMtx.Unlock()
 }
diff --git a/vfs/readervfs/reader.go b/vfs/readervfs/reader.go
index 4312744..098f432 100644
--- a/vfs/readervfs/reader.go
+++ b/vfs/readervfs/reader.go
@@ -3,16 +3,15 @@ package readervfs
 import (
 	"github.com/ncruces/go-sqlite3"
 	"github.com/ncruces/go-sqlite3/util/ioutil"
-	"github.com/ncruces/go-sqlite3/util/vfsutil"
 	"github.com/ncruces/go-sqlite3/vfs"
 )
 
 type readerVFS struct{}
 
 func (readerVFS) Open(name string, flags vfs.OpenFlag) (vfs.File, vfs.OpenFlag, error) {
-	// Temp journals, as used by the sorter, use SliceFile.
+	// Temp journals, as used by the sorter, use a temporary file.
 	if flags&vfs.OPEN_TEMP_JOURNAL != 0 {
-		return &vfsutil.SliceFile{}, flags | vfs.OPEN_MEMORY, nil
+		return vfs.Find("").Open(name, flags)
 	}
 	// Refuse to open all other file types.
 	if flags&vfs.OPEN_MAIN_DB == 0 {
diff --git a/vfs/registry.go b/vfs/registry.go
index 42a2106..32ddfbd 100644
--- a/vfs/registry.go
+++ b/vfs/registry.go
@@ -10,13 +10,17 @@ var (
 
 // Find returns a VFS given its name.
 // If there is no match, nil is returned.
-// If name is empty, the default VFS is returned.
+// If name is empty or "os", the default VFS is returned.
 //
 // https://sqlite.org/c3ref/vfs_find.html
 func Find(name string) VFS {
 	if name == "" || name == "os" {
 		return vfsOS{}
 	}
+	return find(name)
+}
+
+func find(name string) VFS {
 	vfsRegistryMtx.RLock()
 	defer vfsRegistryMtx.RUnlock()
 	return vfsRegistry[name]
@@ -31,11 +35,11 @@ func Register(name string, vfs VFS) {
 		return
 	}
 	vfsRegistryMtx.Lock()
-	defer vfsRegistryMtx.Unlock()
 	if vfsRegistry == nil {
 		vfsRegistry = map[string]VFS{}
 	}
 	vfsRegistry[name] = vfs
+	vfsRegistryMtx.Unlock()
 }
 
 // Unregister unregisters a VFS.
@@ -43,6 +47,6 @@ func Register(name string, vfs VFS) {
 // https://sqlite.org/c3ref/vfs_find.html
 func Unregister(name string) {
 	vfsRegistryMtx.Lock()
-	defer vfsRegistryMtx.Unlock()
 	delete(vfsRegistry, name)
+	vfsRegistryMtx.Unlock()
 }
diff --git a/vfs/vfs.go b/vfs/vfs.go
index d1e1964..6720766 100644
--- a/vfs/vfs.go
+++ b/vfs/vfs.go
@@ -50,8 +50,7 @@ func ExportHostFunctions(env wazero.HostModuleBuilder) wazero.HostModuleBuilder
 }
 
 func vfsFind(ctx context.Context, mod api.Module, zVfsName ptr_t) uint32 {
-	name := util.ReadString(mod, zVfsName, _MAX_NAME)
-	if vfs := Find(name); vfs != nil && vfs != (vfsOS{}) {
+	if find(util.ReadString(mod, zVfsName, _MAX_NAME)) != nil {
 		return 1
 	}
 	return 0