diff --git a/jtftp/protocol/remote_origin_write.py b/jtftp/protocol/remote_origin_write.py
index 9b56bd5..66078df 100644
--- a/jtftp/protocol/remote_origin_write.py
+++ b/jtftp/protocol/remote_origin_write.py
@@ -162,7 +162,7 @@ class RemoteOriginWriteProtocol(asyncio.DatagramProtocol):
         # need to check block numbers
 
         if len(datagram.payload) == self.block_size:
-            self.file.write(datagram.payload)
+            await self.file.write(datagram.payload)
             self.retransmit_task = asyncio.create_task(
                 timed_caller(
                     itertools.chain((0,), self.timeout),