ls does not work for subdirectories about ampy HOT 3 CLOSED

jerryneedell@Ubuntu-Macmini:~/projects/feather52$ ampy ls
lib
sdmount_lib.py
ble_scan.py
sdmount.py
stmpe610_i2c.py
adafruit_stmpe610.mpy
i2c_scan.py
stmpe610_spi.py
paint_nrf52.py
am2320_test.py
I2S_Test_Script.py
stmpe.py
jerryneedell@Ubuntu-Macmini:~/projects/feather52$ ampy ls lib
Traceback (most recent call last):
  File "/usr/local/bin/ampy", line 11, in <module>
    load_entry_point('adafruit-ampy==1.0.5', 'console_scripts', 'ampy')()
  File "/usr/local/lib/python3.5/dist-packages/click/core.py", line 700, in __call__
    return self.main(*args, **kwargs)
  File "/usr/local/lib/python3.5/dist-packages/click/core.py", line 680, in main
    rv = self.invoke(ctx)
  File "/usr/local/lib/python3.5/dist-packages/click/core.py", line 1027, in invoke
    return _process_result(sub_ctx.command.invoke(sub_ctx))
  File "/usr/local/lib/python3.5/dist-packages/click/core.py", line 873, in invoke
    return ctx.invoke(self.callback, **ctx.params)
  File "/usr/local/lib/python3.5/dist-packages/click/core.py", line 508, in invoke
    return callback(*args, **kwargs)
  File "/usr/local/lib/python3.5/dist-packages/ampy/cli.py", line 162, in ls
    for f in board_files.ls(directory, long_format=long_format):
  File "/usr/local/lib/python3.5/dist-packages/ampy/files.py", line 124, in ls
    raise ex
  File "/usr/local/lib/python3.5/dist-packages/ampy/files.py", line 117, in ls
    out = self._pyboard.exec_(textwrap.dedent(command))
  File "/usr/local/lib/python3.5/dist-packages/ampy/pyboard.py", line 267, in exec_
    raise PyboardError('exception', ret, ret_err)
ampy.pyboard.PyboardError: ('exception', b'', b'Traceback (most recent call last):\r\n  File "<stdin>", line 6, in <module>\r\nOSError: [Errno 22] EINVAL\r\n')