IWRL6432BOOST: Exception: Error, Mismatch between requested and actual packet length: act 18043, req 8

When I try to flash the hello world example, as the IWRL6432 documents suggest to try first, I get:

user@userspace:~/ti/MMWAVE_L_SDK_05_04_00_01/tools/boot$ python3 arprog_cmdline.py -p /dev/ttyACM4 -f ../../examples/hello_world/xwrL64xx-evm/m4fss0-0_freertos/ti-arm-clang/hello_world.release.appimage -s SFLASH -t META_IMAGE1
Connecting Com Port....
connect to device
INFO : Port Opened
set break signal
--- please restart the device ---
connection succeeded
downloading [META_IMAGE1] size [35012]
INFO : Port Opened
INFO: Send start download command
Traceback (most recent call last):        ]
  File "/home/user/ti/MMWAVE_L_SDK_05_04_00_01/tools/boot/arprog_cmdline.py", line 94, in <module>
    ldr.download_file(args.source_file, args.target_image_name, 0,0,args.storage)
  File "/home/user/ti/MMWAVE_L_SDK_05_04_00_01/tools/boot/./arprog.py", line 427, in download_file
    if (not self._send_chunk(buff,bufflen)):
  File "/home/user/ti/MMWAVE_L_SDK_05_04_00_01/tools/boot/./arprog.py", line 292, in _send_chunk
    return self._send_command(data)
  File "/home/user/ti/MMWAVE_L_SDK_05_04_00_01/tools/boot/./arprog.py", line 240, in _send_command
    retStatus = self._receive_packet(self.cmdStatusSize)
  File "/home/user/ti/MMWAVE_L_SDK_05_04_00_01/tools/boot/./arprog.py", line 196, in _receive_packet
    raise Exception("Error, Mismatch between requested and actual packet length: act {:d}, req {:d}".format(PacketLength, Length))
Exception: Error, Mismatch between requested and actual packet length: act 18043, req 8

The device is in Device Management Mode, I think, according to the IWRL6432 user guide at least.

Any ideas on why this is happening?


Note: There is no USB0/1 when I connect the EVM in DMM. Instead I get:

crw-rw-rw- 1 root                tty       5,  0 Mar 29 14:58 /dev/tty
crw-rw-rw- 1 root                dialout 166,  5 Mar 29 15:45 /dev/ttyACM5
crw-rw-rw- 1 root                dialout 166,  4 Mar 29 16:00 /dev/ttyACM4