diff --git a/src/calibre/devices/kobo/driver.py b/src/calibre/devices/kobo/driver.py
index 35f89ca91e..1a3344867f 100644
--- a/src/calibre/devices/kobo/driver.py
+++ b/src/calibre/devices/kobo/driver.py
@@ -762,7 +762,7 @@ class KOBO(USBMS):
                     pass
                 else:
                     with open(outpath, 'rb') as src:
-                        shutil.copyfile(src, outfile)
+                        shutil.copyfileobj(src, outfile)
                     return
 
         return USBMS.get_file(self, path, outfile, end_session=end_session)