diff --git a/kmk/firmware.py b/kmk/firmware.py
index 7c3f003..5c2387b 100644
--- a/kmk/firmware.py
+++ b/kmk/firmware.py
@@ -64,6 +64,7 @@ class Firmware:
 
     split_type = None
     split_offsets = ()
+    split_flip = True
     split_master_left = True
     uart = None
 
@@ -86,6 +87,7 @@ class Firmware:
     def _handle_update(self, update):
         # if self.split_type is not None and not self.split_master_left:
             # update[1] += self.split_offsets[update[1]]
+        print(update[1])
 
         if update is not None:
             self._state.matrix_changed(
@@ -115,9 +117,6 @@ class Firmware:
             if self.uart is None:
                 self.uart = busio.UART(board.TX, board.RX, timeout=1)
 
-            # Update column with offset
-            # if self.split_master_left:
-                # update[1] += self.split_offsets[update[1]]
 
             self.uart.write(update)
 
@@ -126,8 +125,11 @@ class Firmware:
             if self.uart is None:
                 self.uart = busio.UART(board.TX, board.RX, timeout=1)
 
-            update = self.uart.read(nbytes=3)
-            return update
+            if self.uart.in_waiting > 0:
+                update = bytearray(self.uart.read())
+                if self.split_master_left:
+                    update[1] += self.split_offsets[update[0]]
+                return update
 
         return None
 
@@ -137,6 +139,9 @@ class Firmware:
         assert self.col_pins, 'no GPIO pins defined for matrix columns'
         assert self.diode_orientation is not None, 'diode orientation must be defined'
 
+        if self.split_flip and not supervisor.runtime.serial_connected:
+            self.col_pins = list(reversed(self.col_pins))
+
         self.matrix = MatrixScanner(
             cols=self.col_pins,
             rows=self.row_pins,
@@ -153,16 +158,16 @@ class Firmware:
         while True:
             if self.split_type is not None and supervisor.runtime.serial_connected:
                 update = self._receive_from_slave()
-                print(str(update))
                 if update is not None:
+                    print(str(update))
                     self._handle_update(update)
 
             for update in self.matrix.scan_for_changes():
                 if update is not None:
                     # Abstract this later. Bluetooth will fail here
                     if supervisor.runtime.serial_connected:
-                        if update is not None:
-                            self._handle_update(update)
+                        print(str(update))
+                        self._handle_update(update)
 
                     else:
                         # This keyboard is a slave, and needs to send data to master
diff --git a/user_keymaps/kdb424/levinson_m4.py b/user_keymaps/kdb424/levinson_m4.py
index 3084822..661d530 100644
--- a/user_keymaps/kdb424/levinson_m4.py
+++ b/user_keymaps/kdb424/levinson_m4.py
@@ -20,7 +20,8 @@ keyboard.tap_time = 900
 keyboard.leader_timeout = 2000
 keyboard.debug_enabled = True
 keyboard.split_type = "UART"
-keyboard.split_offsets = [5, 5, 5, 5]
+keyboard.split_flip = True
+keyboard.split_offsets = [6, 6, 6, 6]
 
 emoticons = compile_unicode_string_sequences({
     # Emoticons, but fancier