diff --git a/pymcuprog/nvmserialupdi.py b/pymcuprog/nvmserialupdi.py
index 1ad7b14..cde78ce 100644
--- a/pymcuprog/nvmserialupdi.py
+++ b/pymcuprog/nvmserialupdi.py
@@ -54,12 +54,13 @@ def __init__(self, transport, device_info, options=""):
         """
         port = transport.serialport
         timeout = transport.timeout
+        dtr = transport.dtr
         baudrate = transport.baudrate
         self.avr = None
         self.options = options
         NvmAccessProvider.__init__(self, device_info)
         self.dut = Dut(device_info)
-        self.avr = UpdiApplication(port, baudrate, self.dut, timeout=timeout)
+        self.avr = UpdiApplication(port, baudrate, self.dut, timeout=timeout, dtr=dtr)
         # Read the device info to set up the UPDI stack variant
         self.avr.read_device_info()
 
diff --git a/pymcuprog/pymcuprog.py b/pymcuprog/pymcuprog.py
index 55dde34..4e4cae9 100644
--- a/pymcuprog/pymcuprog.py
+++ b/pymcuprog/pymcuprog.py
@@ -252,6 +252,11 @@ def main():
                         default="1.0",
                         help="Timeout for read operations to complete (when using -t uart).  Defaults to 1.0s")
 
+    parser.add_argument("--uart-dtr",
+                        type=int,
+                        default=-1,
+                        help="Set serial port DTR line high (0) or low (1). Default for all connections is low.")
+
     parser.add_argument("-i", "--interface",
                         type=str,
                         help="Programming interface to use")
diff --git a/pymcuprog/pymcuprog_main.py b/pymcuprog/pymcuprog_main.py
index f798bf0..7cceca9 100644
--- a/pymcuprog/pymcuprog_main.py
+++ b/pymcuprog/pymcuprog_main.py
@@ -505,7 +505,7 @@ def _setup_tool_connection(args):
     if args.tool == "uart":
         baudrate = _clk_as_int(args)
         # Embedded GPIO/UART tool (eg: raspberry pi) => no USB connection
-        toolconnection = ToolSerialConnection(serialport=args.uart, baudrate=baudrate, timeout=args.uart_timeout)
+        toolconnection = ToolSerialConnection(serialport=args.uart, baudrate=baudrate, timeout=args.uart_timeout, dtr=args.uart_dtr)
     else:
         usb_serial = args.serialnumber
         product = args.tool
diff --git a/pymcuprog/serialupdi/application.py b/pymcuprog/serialupdi/application.py
index 5526031..fdecab3 100644
--- a/pymcuprog/serialupdi/application.py
+++ b/pymcuprog/serialupdi/application.py
@@ -79,12 +79,12 @@ class UpdiApplication:
     :type timeout: int
     """
 
-    def __init__(self, serialport, baud, device=None, timeout=None):
+    def __init__(self, serialport, baud, device=None, timeout=None, dtr=-1):
         self.logger = getLogger(__name__)
         self.device = device
         # Build the UPDI stack:
         # Create a physical
-        self.phy = UpdiPhysical(serialport, baud, timeout)
+        self.phy = UpdiPhysical(serialport, baud, timeout, dtr)
 
         # Create a DL - use 24-bit until otherwise known
         datalink = UpdiDatalink24bit()
diff --git a/pymcuprog/serialupdi/physical.py b/pymcuprog/serialupdi/physical.py
index a9c4742..898ff04 100644
--- a/pymcuprog/serialupdi/physical.py
+++ b/pymcuprog/serialupdi/physical.py
@@ -15,7 +15,7 @@ class UpdiPhysical:
     PDI physical driver using a given serial port at a given baud
     """
 
-    def __init__(self, port, baud=DEFAULT_SERIALUPDI_BAUD, timeout=None):
+    def __init__(self, port, baud=DEFAULT_SERIALUPDI_BAUD, timeout=None, dtr=-1):
         """
         Serial port physical interface for UPDI
 
@@ -42,13 +42,14 @@ def __init__(self, port, baud=DEFAULT_SERIALUPDI_BAUD, timeout=None):
             self.timeout = timeout
         else:
             self.timeout = 1.0
+        self.dtr = dtr
         self.ser = None
 
-        self.initialise_serial(self.port, self.baud, self.timeout)
+        self.initialise_serial(self.port, self.baud, self.timeout, self.dtr)
         # send an initial break as handshake
         self.send([constants.UPDI_BREAK])
 
-    def initialise_serial(self, port, baud, timeout):
+    def initialise_serial(self, port, baud, timeout, dtr):
         """
         Standard serial port initialisation
 
@@ -67,6 +68,9 @@ def initialise_serial(self, port, baud, timeout):
             self.logger.error("Unable to open serial port '%s'", port)
             raise
 
+        if dtr != -1:
+            self.ser.dtr = (dtr != 0)
+
     def _loginfo(self, msg, data):
         if data and isinstance(data[0], str):
             i_data = [ord(x) for x in data]
@@ -109,7 +113,7 @@ def send_double_break(self):
 
         # Re-init at the real baud
         temporary_serial.close()
-        self.initialise_serial(self.port, self.baud, self.timeout)
+        self.initialise_serial(self.port, self.baud, self.timeout, self.dtr)
 
     def send(self, command):
         """
diff --git a/pymcuprog/toolconnection.py b/pymcuprog/toolconnection.py
index c3dde09..cf7e577 100644
--- a/pymcuprog/toolconnection.py
+++ b/pymcuprog/toolconnection.py
@@ -34,7 +34,7 @@ class ToolSerialConnection(ToolConnection):
     """
     serialport = None
 
-    def __init__(self, serialport="COM1", baudrate=DEFAULT_SERIALUPDI_BAUD, timeout=None):
+    def __init__(self, serialport="COM1", baudrate=DEFAULT_SERIALUPDI_BAUD, timeout=None, dtr=-1):
         """
         :param serialport: Serial port name to connect to.
         :type serialport: str
@@ -43,7 +43,9 @@ def __init__(self, serialport="COM1", baudrate=DEFAULT_SERIALUPDI_BAUD, timeout=
         :param timeout: timeout value for serial reading.
             When UPDI is not enabled, attempting to read will return after this timeout period.
         :type timeout: float
+        :type timeout: int
         """
         self.serialport = serialport
         self.baudrate = baudrate
         self.timeout = timeout
+        self.dtr = dtr