diff --git a/libc/kernel/uapi/linux/android/binder.h b/libc/kernel/uapi/linux/android/binder.h
index 2745972..e3b3289 100644
--- a/libc/kernel/uapi/linux/android/binder.h
+++ b/libc/kernel/uapi/linux/android/binder.h
@@ -152,6 +152,7 @@
   TF_STATUS_CODE = 0x08,
   TF_ACCEPT_FDS = 0x10,
   TF_CLEAR_BUF = 0x20,
+  TF_UPDATE_TXN = 0x40,
 };
 struct binder_transaction_data {
   union {