diff --git a/chroot_version_hooks.d/162_post_protobuf_upgrade b/chroot_version_hooks.d/162_post_protobuf_upgrade
new file mode 100644
index 0000000..16f93ee
--- /dev/null
+++ b/chroot_version_hooks.d/162_post_protobuf_upgrade
@@ -0,0 +1,31 @@
+# Copyright 2019 The Chromium OS Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+# Clean local portage caches. This is necessary if there are
+# cros_workon packages.
+sudo rm -rf /var/cache/portage/* /build/*/var/cache/portage/*
+
+# Clean board packages.
+for board_root in /build/* ; do
+  board=${board_root##*/}
+  [[ "${board}" == "bin" || "${board}" == "dev" || \
+     "${board}" == "proc" ]] && continue
+
+  # Find packages using  either protobuf or grpc.
+  PKGS=( $(qdepends-${board} -qCN -Q dev-libs/protobuf && \
+         qdepends-${board} -qCN -Q net-libs/grpc | sort -u))
+  if [[ ${#PKGS[@]} -eq 0 ]]; then
+    continue
+  fi
+
+  echo "Cleaning packages using protobuf or grpc from ${board}"
+  PKGDIR=$(portageq-${board} envvar PKGDIR)
+  cd "${PKGDIR}"
+  # Remove existing binary packages.
+  for pkg in "${PKGS[@]}"; do
+    sudo rm -f "${pkg}"-[0-9]*.tbz2
+  done
+  # Unmerge all packages using either protobuf or grpc.
+  qmerge-${board} -Uqy "${PKGS[@]}"
+done