diff --git a/adaptercore/device_handler.go b/adaptercore/device_handler.go
index 92b6445..ba4040f 100644
--- a/adaptercore/device_handler.go
+++ b/adaptercore/device_handler.go
@@ -324,7 +324,7 @@
 		onuDiscInd := indication.GetOnuDiscInd()
 		log.Infow("Received Onu discovery indication ", log.Fields{"OnuDiscInd": onuDiscInd})
 		sn := dh.stringifySerialNumber(onuDiscInd.SerialNumber)
-		dh.onuDiscIndication(onuDiscInd, sn)
+		go dh.onuDiscIndication(onuDiscInd, sn)
 	case *oop.Indication_OnuInd:
 		onuInd := indication.GetOnuInd()
 		log.Infow("Received Onu indication ", log.Fields{"OnuInd": onuInd})
@@ -728,38 +728,41 @@
 	}
 }
 
-func (dh *DeviceHandler) onuDiscIndication(onuDiscInd *oop.OnuDiscIndication, sn string) error {
+func (dh *DeviceHandler) onuDiscIndication(onuDiscInd *oop.OnuDiscIndication, sn string) {
 	channelID := onuDiscInd.GetIntfId()
 	parentPortNo := IntfIDToPortNo(onuDiscInd.GetIntfId(), voltha.Port_PON_OLT)
+
+	log.Debugw("new-discovery-indication", log.Fields{"sn": sn})
+	dh.lockDevice.Lock()
 	if _, ok := dh.discOnus[sn]; ok {
+		dh.lockDevice.Unlock()
 		log.Debugw("onu-sn-is-already-being-processed", log.Fields{"sn": sn})
-		return nil
+		return
 	}
 
-	dh.lockDevice.Lock()
 	dh.discOnus[sn] = true
+	log.Debugw("new-discovery-indications-list", log.Fields{"discOnus": dh.discOnus})
 	dh.lockDevice.Unlock()
-	// evict the onu serial number from local cache
-	defer func() {
-		delete(dh.discOnus, sn)
-	}()
 
 	kwargs := make(map[string]interface{})
 	if sn != "" {
 		kwargs["serial_number"] = sn
 	} else {
-		log.Error("invalid onu serial number")
-		return errors.New("failed to fetch onu serial number")
+		log.Errorw("invalid onu serial number", log.Fields{"sn": sn})
+		return
 	}
 
 	onuDevice, err := dh.coreProxy.GetChildDevice(context.TODO(), dh.device.Id, kwargs)
 	var onuID uint32
 	if onuDevice == nil || err != nil {
 		//This is the first time ONU discovered. Create an OnuID for it.
-		onuID, err = dh.resourceMgr.GetONUID(onuDiscInd.GetIntfId())
+		ponintfid := onuDiscInd.GetIntfId()
+		dh.lockDevice.Lock()
+		onuID, err = dh.resourceMgr.GetONUID(ponintfid)
+		dh.lockDevice.Unlock()
 		if err != nil {
-			log.Errorw("failed to fetch onuID from resource manager", log.Fields{"err": err})
-			return err
+			log.Errorw("failed to fetch onuID from resource manager", log.Fields{"pon-intf-id": ponintfid, "err": err})
+			return
 		}
 		if onuDevice, err = dh.coreProxy.ChildDeviceDetected(context.TODO(), dh.device.Id, int(parentPortNo),
 			"brcm_openomci_onu", int(channelID),
@@ -767,8 +770,9 @@
 			log.Errorw("Create onu error",
 				log.Fields{"parent_id": dh.device.Id, "ponPort": onuDiscInd.GetIntfId(),
 					"onuID": onuID, "sn": sn, "error": err})
-			return err
+			return
 		}
+		log.Debugw("onu-child-device-added", log.Fields{"onuDevice": onuDevice})
 
 	} else {
 		//ONU already discovered before. Use the same OnuID.
@@ -779,12 +783,16 @@
 	log.Debugw("ONU discovery indication key create", log.Fields{"onuID": onuID,
 		"intfId": onuDiscInd.GetIntfId()})
 	onuKey := dh.formOnuKey(onuDiscInd.GetIntfId(), onuID)
+
+	dh.lockDevice.Lock()
 	dh.onus[onuKey] = NewOnuDevice(onuDevice.Id, onuDevice.Type, onuDevice.SerialNumber, onuID, onuDiscInd.GetIntfId(), onuDevice.ProxyAddress.DeviceId)
+	log.Debugw("new-onu-device-discovered", log.Fields{"onu": dh.onus[onuKey]})
+	dh.lockDevice.Unlock()
 
 	err = dh.coreProxy.DeviceStateUpdate(context.TODO(), onuDevice.Id, common.ConnectStatus_REACHABLE, common.OperStatus_DISCOVERED)
 	if err != nil {
-		log.Errorw("failed to update device state", log.Fields{"DeviceID": onuDevice.Id})
-		return err
+		log.Errorw("failed to update device state", log.Fields{"DeviceID": onuDevice.Id, "err": err})
+		return
 	}
 	log.Debugw("onu-discovered-reachable", log.Fields{"deviceId": onuDevice.Id})
 	//TODO: We put this sleep here to prevent the race between state update and onuIndication
@@ -792,7 +800,7 @@
 	//then the initialisation fails.
 	time.Sleep(1 * time.Second)
 	dh.activateONU(onuDiscInd.IntfId, int64(onuID), onuDiscInd.SerialNumber, sn)
-	return nil
+	return
 }
 
 func (dh *DeviceHandler) onuIndication(onuInd *oop.OnuIndication) {
@@ -831,7 +839,9 @@
 		}
 		if !foundInCache {
 			onuKey := dh.formOnuKey(onuInd.GetIntfId(), onuInd.GetOnuId())
+			dh.lockDevice.Lock()
 			dh.onus[onuKey] = NewOnuDevice(onuDevice.Id, onuDevice.Type, onuDevice.SerialNumber, onuInd.GetOnuId(), onuInd.GetIntfId(), onuDevice.ProxyAddress.DeviceId)
+			dh.lockDevice.Unlock()
 		}
 		dh.updateOnuStates(onuDevice, onuInd, foundInCache)
 
@@ -843,11 +853,11 @@
 }
 
 func (dh *DeviceHandler) updateOnuStates(onuDevice *voltha.Device, onuInd *oop.OnuIndication, foundInCache bool) {
+	log.Debugw("onu-indication-for-state", log.Fields{"onuIndication": onuInd, "DeviceId": onuDevice.Id, "operStatus": onuDevice.OperStatus, "adminStatus": onuDevice.AdminState})
 	dh.updateOnuAdminState(onuInd)
 	// operState
 	if onuInd.OperState == "down" {
-		log.Debugw("inter-adapter-send-onu-ind", log.Fields{"onuIndication": onuInd})
-
+		log.Debugw("sending-interadapter-onu-indication", log.Fields{"onuIndication": onuInd, "DeviceId": onuDevice.Id, "operStatus": onuDevice.OperStatus, "adminStatus": onuDevice.AdminState})
 		// TODO NEW CORE do not hardcode adapter name. Handler needs Adapter reference
 		err := dh.AdapterProxy.SendInterAdapterMessage(context.TODO(), onuInd, ic.InterAdapterMessageType_ONU_IND_REQUEST,
 			"openolt", onuDevice.Type, onuDevice.Id, onuDevice.ProxyAddress.DeviceId, "")
@@ -858,9 +868,11 @@
 	} else if onuInd.OperState == "up" {
 		// Ignore operstatus if device was found in cache
 		if !foundInCache && onuDevice.OperStatus != common.OperStatus_DISCOVERED {
-			log.Warnw("ignore onu indication", log.Fields{"intfID": onuInd.IntfId, "onuID": onuInd.OnuId, "operStatus": onuDevice.OperStatus, "msgOperStatus": onuInd.OperState})
+			log.Warnw("ignore-onu-indication", log.Fields{"intfID": onuInd.IntfId, "onuID": onuInd.OnuId, "operStatus": onuDevice.OperStatus, "msgOperStatus": onuInd.OperState})
 			return
 		}
+		log.Debugw("sending-interadapter-onu-indication", log.Fields{"onuIndication": onuInd, "DeviceId": onuDevice.Id, "operStatus": onuDevice.OperStatus, "adminStatus": onuDevice.AdminState})
+		// TODO NEW CORE do not hardcode adapter name. Handler needs Adapter reference
 		err := dh.AdapterProxy.SendInterAdapterMessage(context.TODO(), onuInd, ic.InterAdapterMessageType_ONU_IND_REQUEST,
 			"openolt", onuDevice.Type, onuDevice.Id, onuDevice.ProxyAddress.DeviceId, "")
 		if err != nil {