diff --git a/voltha/adapters/openolt/openolt_device.py b/voltha/adapters/openolt/openolt_device.py
index 2bc036a..0fb5353 100644
--- a/voltha/adapters/openolt/openolt_device.py
+++ b/voltha/adapters/openolt/openolt_device.py
@@ -19,6 +19,7 @@
 import time
 from scapy.layers.l2 import Ether, Dot1Q
 from transitions import Machine
+from twisted.internet import reactor
 
 from voltha.protos.device_pb2 import Port
 from voltha.adapters.openolt.protos import openolt_pb2
@@ -318,7 +319,7 @@
     def send_proxied_message(self, proxy_address, msg):
         omci = openolt_pb2.OmciMsg(intf_id=proxy_address.channel_id,
                                    onu_id=proxy_address.onu_id, pkt=str(msg))
-        self._grpc.stub.OmciMsgOut(omci)
+        reactor.callInThread(self._grpc.stub.OmciMsgOut, omci)
 
     def update_flow_table(self, flows):
         self.log.debug('No updates here now, all is done in logical flows '
@@ -381,19 +382,9 @@
                        serial_number=serial_number)
         onu = openolt_pb2.Onu(intf_id=intf_id, onu_id=onu_id,
                               serial_number=serial_number)
-        try:
-            self._grpc.stub.ActivateOnu(onu)
-        except grpc.RpcError as grpc_e:
-            if grpc_e.code() == grpc.StatusCode.ALREADY_EXISTS:
-                self.log.info('onu activation in progress',
-                              serial_number=serial_number_str,
-                              e=grpc_e)
-            else:
-                self.log.error('onu activation failed',
-                               serial_number=serial_number_str,
-                               grpc_error=grpc_e)
-        else:
-            self.log.info('onu-activated', serial_number=serial_number_str)
+
+        self.log.info('activating onu', serial_number=serial_number_str)
+        reactor.callInThread(self._grpc.stub.ActivateOnu, onu)
 
     # FIXME - instead of passing child_device around, delete_child_device
     # needs to change to use serial_number.
diff --git a/voltha/adapters/openolt/openolt_flow_mgr.py b/voltha/adapters/openolt/openolt_flow_mgr.py
index 1150d9a..94a15cf 100644
--- a/voltha/adapters/openolt/openolt_flow_mgr.py
+++ b/voltha/adapters/openolt/openolt_flow_mgr.py
@@ -896,7 +896,7 @@
     def add_flow_to_device(self, flow, logical_flow):
         self.log.debug('pushing flow to device', flow=flow)
         try:
-            self.stub.FlowAdd(flow)
+            reactor.callInThread(self.stub.FlowAdd, flow)
         except grpc.RpcError as grpc_e:
             if grpc_e.code() == grpc.StatusCode.ALREADY_EXISTS:
                 self.log.warn('flow already exists', e=grpc_e, flow=flow)