diff --git a/adapters/simulated_olt/adaptercore/simulated_olt.go b/adapters/simulated_olt/adaptercore/simulated_olt.go
index bb6883a..aa6e248 100644
--- a/adapters/simulated_olt/adaptercore/simulated_olt.go
+++ b/adapters/simulated_olt/adaptercore/simulated_olt.go
@@ -222,22 +222,22 @@
 	return errors.New("UnImplemented")
 }
 
-func (so *SimulatedOLT) Download_image(device *voltha.Device, request *voltha.ImageDownload) error {
-	return errors.New("UnImplemented")
+func (so *SimulatedOLT) Download_image(device *voltha.Device, request *voltha.ImageDownload)  (*voltha.ImageDownload, error) {
+	return nil, errors.New("UnImplemented")
 }
 
-func (so *SimulatedOLT) Get_image_download_status(device *voltha.Device, request *voltha.ImageDownload) error {
-	return errors.New("UnImplemented")
+func (so *SimulatedOLT) Get_image_download_status(device *voltha.Device, request *voltha.ImageDownload)  (*voltha.ImageDownload, error) {
+	return nil, errors.New("UnImplemented")
 }
 
-func (so *SimulatedOLT) Cancel_image_download(device *voltha.Device, request *voltha.ImageDownload) error {
-	return errors.New("UnImplemented")
+func (so *SimulatedOLT) Cancel_image_download(device *voltha.Device, request *voltha.ImageDownload)  (*voltha.ImageDownload, error) {
+	return nil, errors.New("UnImplemented")
 }
 
-func (so *SimulatedOLT) Activate_image_update(device *voltha.Device, request *voltha.ImageDownload) error {
-	return errors.New("UnImplemented")
+func (so *SimulatedOLT) Activate_image_update(device *voltha.Device, request *voltha.ImageDownload)  (*voltha.ImageDownload, error) {
+	return nil, errors.New("UnImplemented")
 }
 
-func (so *SimulatedOLT) Revert_image_update(device *voltha.Device, request *voltha.ImageDownload) error {
-	return errors.New("UnImplemented")
+func (so *SimulatedOLT) Revert_image_update(device *voltha.Device, request *voltha.ImageDownload)  (*voltha.ImageDownload, error) {
+	return nil, errors.New("UnImplemented")
 }