RTT studio 使用pyocd对GD32F450ZK下载失败

pyocd pack -f gd32f450zk
  Part         Vendor       Pack                      Version   Installed
---------------------------------------------------------------------------
  GD32F450ZK   GigaDevice   GigaDevice.GD32F4xx_DFP   3.0.3     True
pyocd list
  #   Probe/Board           Unique ID                                          Target
---------------------------------------------------------------------------------------
  0   Arm Air32 CMSIS-DAP   000100011a5a5bb600000000000a2411a5a5a5a597969908   n/a
      LuatOS                Air32 MINI DAPLink

D:\RT-ThreadStudio>cd /d D:\RT-ThreadStudio\repo\Extract\Debugger_Support_Packages\RealThread\PyOCD\0.2.1 
D:\RT-ThreadStudio\repo\Extract\Debugger_Support_Packages\RealThread\PyOCD\0.2.1>pyocd.exe flash --target=GD32F450ZK --erase=auto -a=0x08000000 --frequency=1000000 D:\AAAworkspace\gd32f450_test\Debug\rtthread.bin 
0000617 W Board ID 0001 is not recognized [mbed_board]
0001635 W Overlapping memory regions in file packs\Keil.STM32L4xx_DFP.2.3.0-small.pack (STM32L412C8Tx); deleting outer region. Further warnings will be suppressed for this file. [cmsis_pack]
Exception in thread load-svd:
Traceback (most recent call last):
  File "threading.py", line 1038, in _bootstrap_inner
  File "pyocd\debug\svd\loader.py", line 72, in run
  File "pyocd\debug\svd\loader.py", line 48, in load
  File "pyocd\debug\svd\parser.py", line 74, in for_xml_file
  File "xml\etree\ElementTree.py", line 1218, in parse
  File "xml\etree\ElementTree.py", line 580, in parse
xml.etree.ElementTree.ParseError: XML or text declaration not at start of entity: line 1, column 2
0002968 W Invalid coresight component, cidr=0x0 [rom_table]
0002982 I Loading D:\AAAworkspace\gd32f450_test\Debug\rtthread.bin at 0x08000000 [load_cmd]
0003158 E Error during board uninit: [session]
0003159 C No ACK received [__main__]
执行完毕, 耗时：4312ms.