VOL-63: Image Download and Image Update support
    - download image
    - get image download status
    - cancel image download
    - list all image downloads
    - activate image update
    - revert image update
    - itest added

Change-Id: I95a5f76071679c8787b2f775de24c96d4e7d462f
diff --git a/voltha/adapters/broadcom_onu/broadcom_onu.py b/voltha/adapters/broadcom_onu/broadcom_onu.py
index 732085c..86f82ad 100644
--- a/voltha/adapters/broadcom_onu/broadcom_onu.py
+++ b/voltha/adapters/broadcom_onu/broadcom_onu.py
@@ -112,6 +112,21 @@
     def reboot_device(self, device):
         raise NotImplementedError()
 
+    def download_image(self, device, request):
+        raise NotImplementedError()
+
+    def get_image_download_status(self, device, request):
+        raise NotImplementedError()
+
+    def cancel_image_download(self, device, request):
+        raise NotImplementedError()
+
+    def activate_image_update(self, device, request):
+        raise NotImplementedError()
+
+    def revert_image_update(self, device, request):
+        raise NotImplementedError()
+
     def self_test_device(self, device):
         """
         This is called to Self a device based on a NBI call.