diff --git a/pyusbtin/usbtin.py b/pyusbtin/usbtin.py
index 679353b..be0b167 100644
--- a/pyusbtin/usbtin.py
+++ b/pyusbtin/usbtin.py
@@ -261,6 +261,7 @@ def stop_rx_thread(self):
 
         # tell the thread to exit
         self.rx_thread_state = USBtin.RX_THREAD_TERMINATE
+        self.serial_port.cancel_read()
         while self.rx_thread_state != USBtin.RX_THREAD_STOPPED:
             # wait for thread to end, sleep 1ms
             sleep(0.001)
@@ -272,11 +273,9 @@ def rx_thread(self):
 
         """ process data as long as requested """
         while self.rx_thread_state == USBtin.RX_THREAD_RUNNING:
-            # fetch bytes if available
-            rxcount = self.serial_port.inWaiting()
-            if rxcount > 0:
-                # fetch all data from serial buffer
-                buf = self.serial_port.read(rxcount)
+            # fetch at least one byte of data from serial buffer
+            buf = self.serial_port.read(max(1, self.serial_port.in_waiting))
+            if buf:
                 if PY_VERSION == 2:
                     buf = [ord(b) for b in buf]