tools/pydfu.py: Call set_configuration() on fresh USB device object.

dpgeorge · dpgeorge · commit bb516af1eb97 · 2017-12-14T10:08:37.000+11:00
This call is required before using the device (some operating systems don't need it but others do). Fixes issue adafruit#3476.
diff --git a/tools/pydfu.py b/tools/pydfu.py
@@ -81,6 +81,7 @@ def init():
     if len(devices) > 1:
         raise ValueError("Multiple DFU devices found")
     __dev = devices[0]
+    __dev.set_configuration()
 
     # Claim DFU interface
     usb.util.claim_interface(__dev, __DFU_INTERFACE)
