diff --git a/meta-google/recipes-phosphor/flash/gbmc-update/75-gbmc-upgrade.sh b/meta-google/recipes-phosphor/flash/gbmc-update/75-gbmc-upgrade.sh
new file mode 100644
index 0000000..c94bf5b
--- /dev/null
+++ b/meta-google/recipes-phosphor/flash/gbmc-update/75-gbmc-upgrade.sh
@@ -0,0 +1,66 @@
+#!/bin/bash
+# Copyright 2021 Google LLC
+#
+# 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.
+
+[ -z "${gbmc_upgrade-}" ] || exit
+
+: "${GBMC_UPGRADE_SIG=/tmp/bmc.sig}"
+
+gbmc_upgrade_hook() {
+  [ -n "${bootfile_url-}" ] || return
+
+  local tmpdir
+  tmpdir="$(mktemp -d)" || return
+  gbmc_upgrade_internal || true
+  # SC doesn't know our variable is defined elsewhere
+  # shellcheck disable=SC2153
+  rm -rf -- "$tmpdir" "$GBMC_UPGRADE_SIG" "$GBMC_UPGRADE_IMG"
+}
+
+gbmc_upgrade_fetch() (
+  echo "Fetching $bootfile_url" >&2
+
+  # We only support tarballs at the moment
+  if [[ "$bootfile_url" != *.tar ]]; then
+    echo "Unknown upgrade unpack method: $bootfile_url" >&2
+    return 1
+  fi
+
+  # Ensure some sane output file limit
+  # Currently no BMC image is larger than 64M
+  ulimit -H -f $((96 * 1024 * 1024)) || return
+  wget "$bootfile_url" | tar -xC "$tmpdir" || true
+
+  local sig
+  sig="$(find "$tmpdir" -name 'image-*.sig')" || return
+  local img="${sig%.sig}"
+  mv "$sig" "$GBMC_UPGRADE_SIG" || return
+  mv "$img" "$GBMC_UPGRADE_IMG" || return
+
+  # Regular packages have a VERSION file with the image
+  local imgdir="${sig%/*}"
+  if [ -f "$imgdir/VERSION" ]; then
+    cat "$imgdir/VERSION" || return
+  fi
+
+  # Staging packages have a directory named after the version
+  local vdir="${imgdir##*/}"
+  if [[ "$vdir" =~ ([0-9]+[.]){3}[0-9]+ ]]; then
+    echo "$vdir"
+  fi
+)
+
+GBMC_BR_DHCP_HOOKS+=(gbmc_upgrade_hook)
+
+gbmc_upgrade=1