diff --git a/common/fake_hardware.h b/common/fake_hardware.h
index a0d79fe..6c25183 100644
--- a/common/fake_hardware.h
+++ b/common/fake_hardware.h
@@ -219,8 +219,8 @@
   const char* GetPartitionMountOptions(
       const std::string& partition_name) const override {
 #ifdef __ANDROID__
-    // TODO(b/181182967): This matches the declaration in hardware_android.cc
-    // but ideally shouldn't be duplicated.
+    // TODO(allight): This matches the declaration in hardware_android.cc but
+    // ideally shouldn't be duplicated.
     return "defcontext=u:object_r:postinstall_file:s0";
 #else
     return "";
diff --git a/scripts/brillo_update_payload b/scripts/brillo_update_payload
index 0be2b0d..f36e995 100755
--- a/scripts/brillo_update_payload
+++ b/scripts/brillo_update_payload
@@ -89,12 +89,14 @@
   exit 1
 }
 
-# Loads shflags. We first look at the default install location; then look for
-# crosutils (chroot); finally check our own directory.
+# Loads shflags. We first look at the default install location; then our own
+# directory; finally the parent directory.
 load_shflags() {
   local my_dir="$(dirname "$(readlink -f "$0")")"
   local path
-  for path in /usr/share/misc "${my_dir}"/lib/shflags; do
+  for path in /usr/share/misc \
+    "${my_dir}"/lib/shflags \
+    "${my_dir}"/../lib/shflags; do
     if [[ -r "${path}/shflags" ]]; then
       . "${path}/shflags" || die "Could not load ${path}/shflags."
       return
diff --git a/stable/Android.bp b/stable/Android.bp
index 0af6f1c..73a9c37 100644
--- a/stable/Android.bp
+++ b/stable/Android.bp
@@ -49,6 +49,7 @@
             ],
         },
     },
+    versions: ["1"],
 }
 
 // update_engine_stable_client (type: executable)
diff --git a/stable/aidl_api/libupdate_engine_stable/1/.hash b/stable/aidl_api/libupdate_engine_stable/1/.hash
new file mode 100644
index 0000000..f21562a
--- /dev/null
+++ b/stable/aidl_api/libupdate_engine_stable/1/.hash
@@ -0,0 +1 @@
+526043ea6cb098d53a9c3e778420e64c4e864d8c
diff --git a/stable/aidl_api/libupdate_engine_stable/1/android/os/IUpdateEngineStable.aidl b/stable/aidl_api/libupdate_engine_stable/1/android/os/IUpdateEngineStable.aidl
new file mode 100644
index 0000000..67db18e
--- /dev/null
+++ b/stable/aidl_api/libupdate_engine_stable/1/android/os/IUpdateEngineStable.aidl
@@ -0,0 +1,39 @@
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+///////////////////////////////////////////////////////////////////////////////
+// THIS FILE IS IMMUTABLE. DO NOT EDIT IN ANY CASE.                          //
+///////////////////////////////////////////////////////////////////////////////
+
+// This file is a snapshot of an AIDL file. Do not edit it manually. There are
+// two cases:
+// 1). this is a frozen version file - do not edit this in any case.
+// 2). this is a 'current' file. If you make a backwards compatible change to
+//     the interface (from the latest frozen version), the build system will
+//     prompt you to update this file with `m <name>-update-api`.
+//
+// You must not make a backward incompatible change to any AIDL file built
+// with the aidl_interface module type with versions property set. The module
+// type is used to build AIDL files in a way that they can be used across
+// independently updatable components of the system. If a device is shipped
+// with such a backward incompatible change, it has a high risk of breaking
+// later when a module using the interface is updated, e.g., Mainline modules.
+
+package android.os;
+interface IUpdateEngineStable {
+  void applyPayloadFd(in ParcelFileDescriptor pfd, in long payload_offset, in long payload_size, in String[] headerKeyValuePairs);
+  boolean bind(android.os.IUpdateEngineStableCallback callback);
+  boolean unbind(android.os.IUpdateEngineStableCallback callback);
+}
diff --git a/stable/aidl_api/libupdate_engine_stable/1/android/os/IUpdateEngineStableCallback.aidl b/stable/aidl_api/libupdate_engine_stable/1/android/os/IUpdateEngineStableCallback.aidl
new file mode 100644
index 0000000..dbca127
--- /dev/null
+++ b/stable/aidl_api/libupdate_engine_stable/1/android/os/IUpdateEngineStableCallback.aidl
@@ -0,0 +1,38 @@
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+///////////////////////////////////////////////////////////////////////////////
+// THIS FILE IS IMMUTABLE. DO NOT EDIT IN ANY CASE.                          //
+///////////////////////////////////////////////////////////////////////////////
+
+// This file is a snapshot of an AIDL file. Do not edit it manually. There are
+// two cases:
+// 1). this is a frozen version file - do not edit this in any case.
+// 2). this is a 'current' file. If you make a backwards compatible change to
+//     the interface (from the latest frozen version), the build system will
+//     prompt you to update this file with `m <name>-update-api`.
+//
+// You must not make a backward incompatible change to any AIDL file built
+// with the aidl_interface module type with versions property set. The module
+// type is used to build AIDL files in a way that they can be used across
+// independently updatable components of the system. If a device is shipped
+// with such a backward incompatible change, it has a high risk of breaking
+// later when a module using the interface is updated, e.g., Mainline modules.
+
+package android.os;
+interface IUpdateEngineStableCallback {
+  oneway void onStatusUpdate(int status_code, float percentage);
+  oneway void onPayloadApplicationComplete(int error_code);
+}