make platform zephyr stand alone (#19504)
diff --git a/config/zephyr/app/copy-flashbundle-firmware.cmake b/config/zephyr/app/copy-flashbundle-firmware.cmake
new file mode 100644
index 0000000..93464f7
--- /dev/null
+++ b/config/zephyr/app/copy-flashbundle-firmware.cmake
@@ -0,0 +1,25 @@
+#
+# Copyright (c) 2022 Project CHIP Authors
+#
+# 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.
+#
+
+# Copy the merged.hex file if it exists, otherwise copy zephyr.hex
+
+set(HEX_NAME merged.hex)
+
+if(EXISTS "zephyr/${HEX_NAME}")
+ configure_file("zephyr/${HEX_NAME}" "${FLASHBUNDLE_FIRMWARE}" COPYONLY)
+else()
+ configure_file("zephyr/${KERNEL_HEX_NAME}" "${FLASHBUNDLE_FIRMWARE}" COPYONLY)
+endif()
