diff --git a/rw_core/core/adapter_manager.go b/rw_core/core/adapter_manager.go
index e502ff1..96fceb3 100644
--- a/rw_core/core/adapter_manager.go
+++ b/rw_core/core/adapter_manager.go
@@ -152,8 +152,11 @@
 	if adaptersIf != nil {
 		for _, adapterIf := range adaptersIf.([]interface{}) {
 			if adapter, ok := adapterIf.(*voltha.Adapter); ok {
-				log.Debugw("found-existing-adapter", log.Fields{"adapterId": adapter.Id})
-				return aMgr.addAdapter(adapter, false)
+				if err := aMgr.addAdapter(adapter, false); err != nil {
+					log.Errorw("failed to add adapter", log.Fields{"adapterId": adapter.Id})
+				} else {
+					log.Debugw("adapter added successfully", log.Fields{"adapterId": adapter.Id})
+				}
 			}
 		}
 	} else {
@@ -174,6 +177,8 @@
 			if dType, ok := deviceTypeIf.(*voltha.DeviceType); ok {
 				log.Debugw("found-existing-device-types", log.Fields{"deviceTypes": dTypes})
 				dTypes.Items = append(dTypes.Items, dType)
+			} else {
+				log.Errorw("not an voltha device type", log.Fields{"interface": deviceTypeIf})
 			}
 		}
 		return aMgr.addDeviceTypes(dTypes, false)
diff --git a/rw_core/core/device_agent.go b/rw_core/core/device_agent.go
index a97e12a..4053b46 100755
--- a/rw_core/core/device_agent.go
+++ b/rw_core/core/device_agent.go
@@ -367,6 +367,10 @@
 	// received
 	response := coreutils.NewResponse()
 	dType := agent.adapterMgr.getDeviceType(device.Type)
+	if dType == nil {
+		log.Errorw("non-existent device type", log.Fields{"deviceType": device.Type})
+		return coreutils.DoneResponse(), status.Errorf(codes.FailedPrecondition, "non-existent device type %s", device.Type)
+	}
 	if !dType.AcceptsAddRemoveFlowUpdates {
 
 		if len(updatedAllGroups) != 0 && reflect.DeepEqual(existingGroups.Items, updatedAllGroups) && len(updatedAllFlows) != 0 && reflect.DeepEqual(existingFlows.Items, updatedAllFlows) {
@@ -463,6 +467,10 @@
 	// Send update to adapters
 	response := coreutils.NewResponse()
 	dType := agent.adapterMgr.getDeviceType(device.Type)
+	if dType == nil {
+		log.Errorw("non-existent device type", log.Fields{"deviceType": device.Type})
+		return coreutils.DoneResponse(), status.Errorf(codes.FailedPrecondition, "non-existent device type %s", device.Type)
+	}
 	if !dType.AcceptsAddRemoveFlowUpdates {
 		if len(groupsToKeep) != 0 && reflect.DeepEqual(existingGroups.Items, groupsToKeep) && len(flowsToKeep) != 0 && reflect.DeepEqual(existingFlows.Items, flowsToKeep) {
 			log.Debugw("nothing-to-update", log.Fields{"deviceId": agent.deviceID, "flowsToDel": flowsToDel, "groupsToDel": groupsToDel})
@@ -536,6 +544,10 @@
 
 	response := coreutils.NewResponse()
 	dType := agent.adapterMgr.getDeviceType(device.Type)
+	if dType == nil {
+		log.Errorw("non-existent device type", log.Fields{"deviceType": device.Type})
+		return coreutils.DoneResponse(), status.Errorf(codes.FailedPrecondition, "non-existent device type %s", device.Type)
+	}
 
 	// Process bulk flow update differently than incremental update
 	if !dType.AcceptsAddRemoveFlowUpdates {