diff --git a/klippy/extras/bus.py b/klippy/extras/bus.py
index 4121c1c8..4490efe4 100644
--- a/klippy/extras/bus.py
+++ b/klippy/extras/bus.py
@@ -180,6 +180,13 @@ class MCU_I2C:
         self.cmd_queue = self.mcu.alloc_command_queue()
         self.mcu.register_config_callback(self.build_config)
         self.i2c_write_cmd = self.i2c_read_cmd = None
+        printer = self.mcu.get_printer()
+        printer.register_event_handler("klippy:connect", self._handle_connect)
+        # backward support i2c_write inside the init section
+        self._to_write = []
+    def _handle_connect(self):
+        for data in self._to_write:
+            self.i2c_write(data)
     def get_oid(self):
         return self.oid
     def get_mcu(self):
@@ -207,10 +214,7 @@ class MCU_I2C:
             cq=self.cmd_queue)
     def i2c_write(self, data, minclock=0, reqclock=0):
         if self.i2c_write_cmd is None:
-            # Send setup message via mcu initialization
-            data_msg = "".join(["%02x" % (x,) for x in data])
-            self.mcu.add_config_cmd("i2c_write oid=%d data=%s" % (
-                self.oid, data_msg), is_init=True)
+            self._to_write.append(data)
             return
         self.i2c_write_cmd.send([self.oid, data],
                                 minclock=minclock, reqclock=reqclock)