diff --git a/kitty/parser.c b/kitty/parser.c
index b82a6dfc6..eb82e5d75 100644
--- a/kitty/parser.c
+++ b/kitty/parser.c
@@ -1170,7 +1170,7 @@ accumulate_osc(Screen *screen, uint32_t ch, PyObject DUMP_UNUSED *dump_callback,
         default:
             if (screen->parser_buf_pos >= PARSER_BUF_SZ - 1) {
                 if (handle_extended_osc_code(screen)) *extended_osc_code = true;
-                else REPORT_ERROR("OSC sequence too long, truncating.");
+                else REPORT_ERROR("OSC sequence too long (> %d bytes) truncating.", PARSER_BUF_SZ);
                 return true;
             }
             screen->parser_buf[screen->parser_buf_pos++] = ch;
diff --git a/kitty_tests/file_transmission.py b/kitty_tests/file_transmission.py
index 6036bf19b..cd8e26ff5 100644
--- a/kitty_tests/file_transmission.py
+++ b/kitty_tests/file_transmission.py
@@ -164,7 +164,7 @@ class PtyFileTransmission(FileTransmission):
         self.pty.callbacks.ftc = self
 
     def write_ftc_to_child(self, payload: FileTransmissionCommand, appendleft: bool = False, use_pending: bool = True) -> bool:
-        self.pty.write_to_child('\x1b]' + payload.serialize(prefix_with_osc_code=True) + '\x1b\\', flush=True)
+        self.pty.write_to_child('\x1b]' + payload.serialize(prefix_with_osc_code=True) + '\x1b\\', flush=False)
 
 
 class TransferPTY(PTY):