diff --git a/go.mod b/go.mod
index 740f6c3..e218323 100644
--- a/go.mod
+++ b/go.mod
@@ -3,9 +3,9 @@ module github.com/ncruces/go-sqlite3
 go 1.24.0
 
 require (
-	github.com/ncruces/aa v0.3.5
 	github.com/ncruces/julianday v1.0.0
-	github.com/ncruces/sort v0.1.5
+	github.com/ncruces/sort v0.1.6
+	github.com/ncruces/wbt v0.1.0
 	github.com/tetratelabs/wazero v1.9.0
 	golang.org/x/sys v0.36.0
 )
diff --git a/go.sum b/go.sum
index e753c04..5725e4a 100644
--- a/go.sum
+++ b/go.sum
@@ -2,12 +2,12 @@ github.com/dchest/siphash v1.2.3 h1:QXwFc8cFOR2dSa/gE6o/HokBMWtLUaNDVd+22aKHeEA=
 github.com/dchest/siphash v1.2.3/go.mod h1:0NvQU092bT0ipiFN++/rXm69QG9tVxLAlQHIXMPAkHc=
 github.com/google/uuid v1.6.0 h1:NIvaJDMOsjHA8n1jAhLSgzrAzy1Hgr+hNrb57e+94F0=
 github.com/google/uuid v1.6.0/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
-github.com/ncruces/aa v0.3.5 h1:zVUBi8FS7Ah0IuoXQv9JPis4KFuQdIzzf48vuOrxiW0=
-github.com/ncruces/aa v0.3.5/go.mod h1:ctOw1LVqfuqzqg2S9LlR045bLAiXtaTiPMCL3zzl7Ik=
 github.com/ncruces/julianday v1.0.0 h1:fH0OKwa7NWvniGQtxdJRxAgkBMolni2BjDHaWTxqt7M=
 github.com/ncruces/julianday v1.0.0/go.mod h1:Dusn2KvZrrovOMJuOt0TNXL6tB7U2E8kvza5fFc9G7g=
-github.com/ncruces/sort v0.1.5 h1:fiFWXXAqKI8QckPf/6hu/bGFwcEPrirIOFaJqWujs4k=
-github.com/ncruces/sort v0.1.5/go.mod h1:obJToO4rYr6VWP0Uw5FYymgYGt3Br4RXcs/JdKaXAPk=
+github.com/ncruces/sort v0.1.6 h1:TrsJfGRH1AoWoaeB4/+gCohot9+cA6u/INaH5agIhNk=
+github.com/ncruces/sort v0.1.6/go.mod h1:obJToO4rYr6VWP0Uw5FYymgYGt3Br4RXcs/JdKaXAPk=
+github.com/ncruces/wbt v0.1.0 h1:DnekGqKcV3qnItd59CwldIAwvbosmWNddPPJSp9t2jk=
+github.com/ncruces/wbt v0.1.0/go.mod h1:DtF92amvMxH69EmBFUSFWRDAlo6hOEfoNQnClxj9C/c=
 github.com/psanford/httpreadat v0.1.0 h1:VleW1HS2zO7/4c7c7zNl33fO6oYACSagjJIyMIwZLUE=
 github.com/psanford/httpreadat v0.1.0/go.mod h1:Zg7P+TlBm3bYbyHTKv/EdtSJZn3qwbPwpfZ/I9GKCRE=
 github.com/tetratelabs/wazero v1.9.0 h1:IcZ56OuxrtaEz8UYNRHBrUa9bYeX9oVY93KspZZBf/I=
diff --git a/sqlite3/download.sh b/sqlite3/download.sh
index b510b1f..081a447 100755
--- a/sqlite3/download.sh
+++ b/sqlite3/download.sh
@@ -4,6 +4,8 @@ set -euo pipefail
 cd -P -- "$(dirname -- "$0")"
 
 curl -#OL "https://sqlite.org/2025/sqlite-amalgamation-3500400.zip"
+openssl dgst -sha3-256 sqlite-amalgamation-*.zip | \
+grep f131b68e6ba5fb891cc13ebb5ff9555054c77294cb92d8d1268bad5dba4fa2a1
 unzip -d . sqlite-amalgamation-*.zip
 mv sqlite-amalgamation-*/sqlite3.c .
 mv sqlite-amalgamation-*/sqlite3.h .
diff --git a/vfs/mvcc/mvcc.go b/vfs/mvcc/mvcc.go
index e74522a..b49e90e 100644
--- a/vfs/mvcc/mvcc.go
+++ b/vfs/mvcc/mvcc.go
@@ -6,10 +6,10 @@ import (
 	"sync"
 	"time"
 
-	"github.com/ncruces/aa"
 	"github.com/ncruces/go-sqlite3"
 	"github.com/ncruces/go-sqlite3/util/vfsutil"
 	"github.com/ncruces/go-sqlite3/vfs"
+	"github.com/ncruces/wbt"
 )
 
 type mvccVFS struct{}
@@ -68,9 +68,9 @@ func (mvccVFS) FullPathname(name string) (string, error) {
 }
 
 type mvccDB struct {
-	data   *aa.Tree[int64, string] // +checklocks:mtx
-	owner  *mvccFile               // +checklocks:mtx
-	waiter *sync.Cond              // +checklocks:mtx
+	data   *wbt.Tree[int64, string] // +checklocks:mtx
+	owner  *mvccFile                // +checklocks:mtx
+	waiter *sync.Cond               // +checklocks:mtx
 
 	name string
 	refs int // +checklocks:memoryMtx
@@ -97,7 +97,7 @@ func (m *mvccDB) fork() *mvccDB {
 
 type mvccFile struct {
 	*mvccDB
-	data     *aa.Tree[int64, string]
+	data     *wbt.Tree[int64, string]
 	lock     vfs.LockLevel
 	readOnly bool
 }