我在用STMCubeProgrammer 下载u-boot到STM32MP157f-ev1时，出现了下面的问题，请教各位大神这是什么原因引起的？
  09:26:24 : Read TSV File: C:\stm32mpu\stm32mp1\FlashLayout_emmc_stm32mp157f-ev1-trusted.tsv
  09:26:24 : Number of partitions: 9
  09:26:29 : Start Embedded Flashing service
  09:26:29 : Memory Programming ...
  09:26:29 : Opening and parsing file: tf-a-stm32mp157f-ev1-usb.stm32
  09:26:29 :   File          : tf-a-stm32mp157f-ev1-usb.stm32
  09:26:29 :   Size          : 225572 Bytes
  09:26:29 :   Partition ID  : 0x01
  09:26:29 : Download in Progress:
  09:26:29 : File download complete
  09:26:29 : Time elapsed during download operation: 00:00:00.496
  09:26:29 : RUNNING Program ...
  09:26:29 :   PartID:      :0x01
  09:26:54:674 : DFU status = 14
  09:26:54:687 : DFU State = 10
  09:26:54:687 : an error occured after sending the clear status request
  09:26:54:688 : Status: errUNKNOWN, State: dfuERROR
  09:26:54:688 : sending a clear status request

  09:28:24:682 : DFU status = 14
  09:28:24:682 : DFU State = 10
  09:28:24:682 : an error occured after sending the clear status request
  09:28:24:683 : Status: errUNKNOWN, State: dfuERROR
  09:28:24:683 : unable to switch the device to dfuIDLE state
  09:28:24:683 : Error: an error occured while uploading data from the virtual partition 0xF1
  09:28:24:698 : Request detach value = 0
  09:28:24:698 : Start operation done successfully at partition 0x01
  09:28:24:698 : sending a set alternate setting request with index: 5
  09:28:24:698 : receiving packet
  09:28:29:683 : DFU status = 14
  09:28:29:683 : DFU State = 10
  09:28:29:684 : sending a clear status request
  09:28:39:685 : DFU status = 14
  09:28:39:685 : DFU State = 10
  09:28:39:685 : an error occured after sending the clear status request
  09:28:39:685 : Status: errUNKNOWN, State: dfuERROR
  09:28:39:685 : sending a clear status request
  09:28:49:686 : DFU status = 14
  09:28:49:686 : DFU State = 10
  09:28:49:686 : an error occured after sending the clear status request
  09:28:49:686 : Status: errUNKNOWN, State: dfuERROR
  09:28:49:686 : sending a clear status request
  09:28:59:687 : DFU status = 14
  09:28:59:687 : DFU State = 10
  09:28:59:687 : an error occured after sending the clear status request
  09:28:59:687 : Status: errUNKNOWN, State: dfuERROR
  09:28:59:687 : sending a clear status request
  09:29:09:688 : DFU status = 14
  09:29:09:689 : DFU State = 10
  09:29:09:690 : an error occured after sending the clear status request
  09:29:09:690 : Status: errUNKNOWN, State: dfuERROR
  09:29:09:691 : sending a clear status request
  09:29:19:690 : DFU status = 14
  09:29:19:691 : DFU State = 10
  09:29:19:691 : an error occured after sending the clear status request
  09:29:19:691 : Status: errUNKNOWN, State: dfuERROR
  09:29:19:692 : sending a clear status request
  09:29:29:691 : DFU status = 14
  09:29:29:691 : DFU State = 10
  09:29:29:691 : an error occured after sending the clear status request
  09:29:29:692 : Status: errUNKNOWN, State: dfuERROR
  09:29:29:692 : sending a clear status request
  09:29:39:692 : DFU status = 14
  09:29:39:692 : DFU State = 10
  09:29:39:692 : an error occured after sending the clear status request
  09:29:39:693 : Status: errUNKNOWN, State: dfuERROR
  09:29:39:693 : sending a clear status request
  09:29:49:692 : DFU status = 14
  09:29:49:692 : DFU State = 10
  09:29:49:693 : an error occured after sending the clear status request
  09:29:49:693 : Status: errUNKNOWN, State: dfuERROR
  09:29:49:693 : sending a clear status request
  09:29:59:694 : DFU status = 14
  09:29:59:695 : DFU State = 10
  09:29:59:695 : an error occured after sending the clear status request
  09:29:59:696 : Status: errUNKNOWN, State: dfuERROR
  09:29:59:696 : sending a clear status request
  09:30:09:695 : DFU status = 14
  09:30:09:696 : DFU State = 10
  09:30:09:696 : an error occured after sending the clear status request
  09:30:09:697 : Status: errUNKNOWN, State: dfuERROR
  09:30:09:698 : unable to switch the device to dfuIDLE state
  09:30:09:698 : Error: an error occured while uploading data from the virtual partition 0xF1
  09:30:09:713 : Received PhaseID == 0xFF, system is going to reboot
  09:30:39:699 : Warning: Connection to device 0x500 is lost
  09:31:44:997 : Disconnected from device.
  09:31:44:997 : STLinkUSBDriver.dll loaded