STLink Error (9): Get IDCODE Error

I am using a NUCLEO-L476RG board, and I have removed the CN2 jumpers, which would use the ST-Link instead of the Nucleo. When I run a flashing command with the following command line:
pyocd flash mbed_blinky.bin --target stm32l476rg
I get the following error:

0001855:ERROR:__main__:uncaught exception: STLink error (9): Get IDCODE error
Traceback (most recent call last):
  File "c:\python27\lib\site-packages\pyocd\__main__.py", line 329, in run
    self._COMMANDS[self._args.cmd](self)
  File "c:\python27\lib\site-packages\pyocd\__main__.py", line 448, in do_flash
    **convert_session_options(self._args.options))
  File "c:\python27\lib\site-packages\pyocd\core\helpers.py", line 199, in session_with_chosen_probe
    session.open()
  File "c:\python27\lib\site-packages\pyocd\core\session.py", line 300, in open
    self._board.init()
  File "c:\python27\lib\site-packages\pyocd\board\board.py", line 70, in init
    self.target.init()
  File "c:\python27\lib\site-packages\pyocd\core\coresight_target.py", line 152, in init
    seq.invoke()
  File "c:\python27\lib\site-packages\pyocd\utility\sequencer.py", line 189, in invoke
    resultSequence = call()
  File "c:\python27\lib\site-packages\pyocd\coresight\dap.py", line 100, in init
    self.link.connect()
  File "c:\python27\lib\site-packages\pyocd\probe\stlink_probe.py", line 114, in connect
    self._link.enter_debug(STLink.Protocol.SWD)
  File "c:\python27\lib\site-packages\pyocd\probe\stlink\stlink.py", line 215, in enter_debug
    self._check_status(response)
  File "c:\python27\lib\site-packages\pyocd\probe\stlink\stlink.py", line 253, in _check_status
    raise exceptions.ProbeError(error_message)
ProbeError: STLink error (9): Get IDCODE error

I have updated the ST-Link firmware to the latest one (V2J34M25), yet I get this issue. Anyone with similar issues and have solved it?

Start by reproducing the command pyocd flash mbed_blinky.bin --target stm32l476rg with the NUCLEO-L476RG and removed CN2 jumpers. Trace the failure through pyocd/probe/stlink/stlink.py, stlink_probe.py, and coresight/dap.py, then determine whether the ST-Link connection can obtain the target IDCODE; done means the cause is identified and the flashing command succeeds or the limitation is documented.