diff --git a/klippy/chelper.py b/klippy/chelper.py
index 99ec3f4f..5b7837ee 100644
--- a/klippy/chelper.py
+++ b/klippy/chelper.py
@@ -39,8 +39,7 @@ defs_serialqueue = """
         double sent_time, receive_time;
     };
 
-    struct serialqueue *serialqueue_alloc(int serial_fd, double baud_adjust
-        , int write_only);
+    struct serialqueue *serialqueue_alloc(int serial_fd, int write_only);
     void serialqueue_exit(struct serialqueue *sq);
     struct command_queue *serialqueue_alloc_commandqueue(void);
     void serialqueue_send(struct serialqueue *sq, struct command_queue *cq
@@ -49,6 +48,7 @@ defs_serialqueue = """
         , struct command_queue *cq, uint32_t *data, int len
         , uint64_t min_clock, uint64_t req_clock);
     void serialqueue_pull(struct serialqueue *sq, struct pull_queue_message *pqm);
+    void serialqueue_set_baud_adjust(struct serialqueue *sq, double baud_adjust);
     void serialqueue_set_clock_est(struct serialqueue *sq, double est_clock
         , double last_ack_time, uint64_t last_ack_clock);
     void serialqueue_flush_ready(struct serialqueue *sq);
diff --git a/klippy/serialhdl.py b/klippy/serialhdl.py
index cac2ef9f..619d46ce 100644
--- a/klippy/serialhdl.py
+++ b/klippy/serialhdl.py
@@ -9,7 +9,7 @@ import serial
 import msgproto, chelper
 
 class SerialReader:
-    BITS_PER_BYTE = 10
+    BITS_PER_BYTE = 10.
     def __init__(self, reactor, serialport, baud):
         self.reactor = reactor
         self.serialport = serialport
@@ -60,22 +60,17 @@ class SerialReader:
         logging.info("Starting serial connect")
         self.ser = serial.Serial(self.serialport, self.baud, timeout=0)
         stk500v2_leave(self.ser)
-        baud_adjust = float(self.BITS_PER_BYTE) / self.baud
-        self.serialqueue = self.ffi_lib.serialqueue_alloc(
-            self.ser.fileno(), baud_adjust, 0)
+        self.serialqueue = self.ffi_lib.serialqueue_alloc(self.ser.fileno(), 0)
         SerialBootStrap(self)
         self.background_thread = threading.Thread(target=self._bg_thread)
         self.background_thread.start()
     def connect_file(self, debugoutput, dictionary, pace=False):
         self.ser = debugoutput
         self.msgparser.process_identify(dictionary, decompress=False)
-        baud_adjust = 0.
         est_clock = 1000000000000.
         if pace:
-            baud_adjust = float(self.BITS_PER_BYTE) / self.baud
             est_clock = self.msgparser.config['CLOCK_FREQ']
-        self.serialqueue = self.ffi_lib.serialqueue_alloc(
-            self.ser.fileno(), baud_adjust, 1)
+        self.serialqueue = self.ffi_lib.serialqueue_alloc(self.ser.fileno(), 1)
         self.est_clock = est_clock
         self.last_ack_time = time.time()
         self.last_ack_clock = 0
@@ -241,6 +236,11 @@ class SerialBootStrap:
         logging.info("MCU version: %s" % (self.serial.msgparser.version,))
         self.serial.unregister_callback('identify_response')
         self.serial.register_callback(self.serial.handle_unknown, '#unknown')
+        mcu_baud = float(self.serial.msgparser.config.get('SERIAL_BAUD', 0.))
+        if mcu_baud:
+            baud_adjust = self.serial.BITS_PER_BYTE / mcu_baud
+            self.serial.ffi_lib.serialqueue_set_baud_adjust(
+                self.serial.serialqueue, baud_adjust)
         get_status = self.serial.msgparser.lookup_command('get_status')
         self.serial.status_cmd = get_status.encode()
         with self.serial.lock:
diff --git a/klippy/serialqueue.c b/klippy/serialqueue.c
index 60ceeb4b..b3451ad6 100644
--- a/klippy/serialqueue.c
+++ b/klippy/serialqueue.c
@@ -770,11 +770,10 @@ background_thread(void *data)
 
 // Create a new 'struct serialqueue' object
 struct serialqueue *
-serialqueue_alloc(int serial_fd, double baud_adjust, int write_only)
+serialqueue_alloc(int serial_fd, int write_only)
 {
     struct serialqueue *sq = malloc(sizeof(*sq));
     memset(sq, 0, sizeof(*sq));
-    sq->baud_adjust = baud_adjust;
 
     // Reactor setup
     sq->serial_fd = serial_fd;
@@ -961,6 +960,14 @@ exit:
     pthread_mutex_unlock(&sq->lock);
 }
 
+void
+serialqueue_set_baud_adjust(struct serialqueue *sq, double baud_adjust)
+{
+    pthread_mutex_lock(&sq->lock);
+    sq->baud_adjust = baud_adjust;
+    pthread_mutex_unlock(&sq->lock);
+}
+
 // Set the estimated clock rate of the mcu on the other end of the
 // serial port
 void
diff --git a/klippy/serialqueue.h b/klippy/serialqueue.h
index 229fb216..80ecd9c5 100644
--- a/klippy/serialqueue.h
+++ b/klippy/serialqueue.h
@@ -43,8 +43,7 @@ struct pull_queue_message {
 };
 
 struct serialqueue;
-struct serialqueue *serialqueue_alloc(int serial_fd, double baud_adjust
-                                      , int write_only);
+struct serialqueue *serialqueue_alloc(int serial_fd, int write_only);
 void serialqueue_exit(struct serialqueue *sq);
 struct command_queue *serialqueue_alloc_commandqueue(void);
 void serialqueue_send_batch(struct serialqueue *sq, struct command_queue *cq
@@ -56,6 +55,7 @@ void serialqueue_encode_and_send(struct serialqueue *sq, struct command_queue *c
                                  , uint32_t *data, int len
                                  , uint64_t min_clock, uint64_t req_clock);
 void serialqueue_pull(struct serialqueue *sq, struct pull_queue_message *pqm);
+void serialqueue_set_baud_adjust(struct serialqueue *sq, double baud_adjust);
 void serialqueue_set_clock_est(struct serialqueue *sq, double est_clock
                                , double last_ack_time, uint64_t last_ack_clock);
 void serialqueue_flush_ready(struct serialqueue *sq);
diff --git a/scripts/buildcommands.py b/scripts/buildcommands.py
index 6bb47341..af9926ca 100644
--- a/scripts/buildcommands.py
+++ b/scripts/buildcommands.py
@@ -153,7 +153,7 @@ def build_identify(cmd_by_id, msg_to_id, responses, static_strings
     data['commands'] = sorted(cmd_by_id.keys())
     data['responses'] = sorted(responses)
     data['static_strings'] = static_strings
-    configlist = ['MCU', 'CLOCK_FREQ']
+    configlist = ['MCU', 'CLOCK_FREQ', 'SERIAL_BAUD']
     data['config'] = dict((i, config['CONFIG_'+i]) for i in configlist
                           if 'CONFIG_'+i in config)
     data['version'] = version