diff --git a/zefie_wtvp_minisrv/app.js b/zefie_wtvp_minisrv/app.js
index 7a84ef55..c7810f1b 100644
--- a/zefie_wtvp_minisrv/app.js
+++ b/zefie_wtvp_minisrv/app.js
@@ -736,27 +736,30 @@ async function sendToClient(socket, headers_obj, data) {
     }
 }
 
-async function sendToSocket(socket, data, chunk_offset = 0) {
+async function sendToSocket(socket, data) {
     // buffer size = lesser of minisrv_config.config.chunk_size or size remaining
     var chunk_size = 16384;
     var can_write = true;
-    var data_left = 0;
-    while (data_left != data.byteLength && can_write) {
-        var data_left = (data.byteLength - chunk_offset);
-        if (data_left === 0) break;
+    var expected_data_out = 0;
+    while ((socket.bytesWritten == 0 || socket.bytesWritten != expected_data_out) && can_write) {
+        if (expected_data_out === 0) expected_data_out = data.byteLength + (socket_sessions[socket.id].socket_total_written || 0);
+        if (socket.bytesWritten == expected_data_out) break;
 
+        var data_left = (expected_data_out - socket.bytesWritten);
         var buffer_size = (data_left >= chunk_size) ? chunk_size : data_left;
+        var offset = (data.byteLength - data_left);
         var chunk = new Buffer.alloc(buffer_size);
-        chunk_offset += data.copy(chunk, 0, chunk_offset, (chunk_offset + buffer_size));
+        data.copy(chunk, 0, offset, (offset + buffer_size));
         can_write = socket.write(chunk);
         if (!can_write) {
             socket.once('drain', function () {
-                sendToSocket(socket, data, socket.bytesWritten);
+                sendToSocket(socket, data);
             });
             break;
         }
     }
-    if (data_left == data.byteLength) {
+    if (socket.bytesWritten == expected_data_out) {
+        socket_sessions[socket.id].socket_total_written = socket.bytesWritten;
         if (socket_sessions[socket.id].expecting_post_data) delete socket_sessions[socket.id].expecting_post_data;
         if (socket_sessions[socket.id].header_buffer) delete socket_sessions[socket.id].header_buffer;
         if (socket_sessions[socket.id].secure_buffer) delete socket_sessions[socket.id].secure_buffer;