Can not find ODdrive

After doing firmware update,I encounter such an error:

.. (sector 0/6) 
Traceback (most recent call last):
  File "/usr/local/bin/odrivetool", line 142, in <module>
    odrive.dfu.launch_dfu(args, logger, app_shutdown_token)
  File "/usr/local/lib/python3.6/dist-packages/odrive/dfu.py", line 455, in launch_dfu
    update_device(device, firmware, logger, cancellation_token)
  File "/usr/local/lib/python3.6/dist-packages/odrive/dfu.py", line 374, in update_device
    dfudev.erase_sector(sector)
  File "/usr/local/lib/python3.6/dist-packages/odrive/dfuse/DfuDevice.py", line 173, in erase_sector
    status = self.wait_while_state(DfuState.DFU_DOWNLOAD_BUSY, timeout=sector['len']/32)
  File "/usr/local/lib/python3.6/dist-packages/odrive/dfuse/DfuDevice.py", line 106, in wait_while_state
    status = self.get_status(timeout=actual_timeout)
  File "/usr/local/lib/python3.6/dist-packages/odrive/dfuse/DfuDevice.py", line 62, in get_status
    status = self.control_msg(DFU_REQUEST_RECEIVE, DFU_GETSTATUS, 0, 6, timeout=timeout)
  File "/usr/local/lib/python3.6/dist-packages/odrive/dfuse/DfuDevice.py", line 49, in control_msg
    return self.dev.ctrl_transfer(requestType, request, value, self.intf.bInterfaceNumber, buffer, timeout=timeout)
  File "/usr/local/lib/python3.6/dist-packages/usb/core.py", line 1043, in ctrl_transfer
    self.__get_timeout(timeout))
  File "/usr/local/lib/python3.6/dist-packages/usb/backend/libusb1.py", line 884, in ctrl_transfer
    timeout))
  File "/usr/local/lib/python3.6/dist-packages/usb/backend/libusb1.py", line 595, in _check
    raise USBError(_strerror(ret), ret, _libusb_errno[ret])
usb.core.USBError: [Errno 110] Operation timed out

and then,my pc(ubuntu 18.04) can not find ODrive

$ lsusb
Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 001 Device 061: ID 1c4f:0002 SiGma Micro Keyboard TRACER Gamma Ivory
Bus 001 Device 003: ID 1c4f:0034 SiGma Micro 
Bus 001 Device 050: ID 148f:7601 Ralink Technology, Corp. MT7601U Wireless Adapter
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
$ (lsusb -d 1209:0d32 -v; lsusb -d 0483:df11 -v) | grep iSerial
$

what should I do?

If you can’t see ODrive in lsusb when the switch is in DFU mode, you’ll have to flash the controller with an STLink. See this page https://docs.odriverobotics.com/odrivetool#flashing-with-an-stlink