diff --git a/rshell/pyboard.py b/rshell/pyboard.py
index 92c8d93..d9d4798 100755
--- a/rshell/pyboard.py
+++ b/rshell/pyboard.py
@@ -123,7 +123,22 @@ def __init__(self, device, baudrate=115200, user='micro', password='python'):
             self.serial = TelnetToSerial(device, user, password, read_timeout=10)
         else:
             import serial
-            self.serial = serial.Serial(device, baudrate=baudrate, interCharTimeout=1)
+            done = False
+            for attempt in range(20):
+                try:
+                    self.serial = serial.Serial(device, baudrate=baudrate, interCharTimeout=1)
+                    done = True
+                    break
+                except OSError:
+                    if attempt == 0:
+                        sys.stdout.write('Waiting for pyboard ')
+                time.sleep(1)
+                sys.stdout.write('.')
+                sys.stdout.flush()
+            print()
+            if not done:
+                print("Failed to access device")
+                sys.exit(1)
 
     def close(self):
         self.serial.close()