diff --git a/tools/pyboard.py b/tools/pyboard.py
index f1ccc59b9..51806a329 100755
--- a/tools/pyboard.py
+++ b/tools/pyboard.py
@@ -567,7 +567,7 @@ def main():
         # do filesystem commands, if given
         if args.filesystem:
             filesystem_command(pyb, args.files)
-            args.files.clear()
+            del args.files[:]
 
         # run the command, if given
         if args.command is not None: