diff --git a/default.xml b/default.xml
index 81c1a48..70aaf2e 100644
--- a/default.xml
+++ b/default.xml
@@ -4,7 +4,7 @@
   <remote  name="aosp"
            fetch="https://android.googlesource.com"
            review="https://android-review.googlesource.com/" />
-  <default revision="refs/tags/android-9.0.0_r16"
+  <default revision="refs/tags/android-9.0.0_r21"
            remote="aosp"
            sync-c="true"
            sync-j="12" />