Arty 100T - Failed telnet connection on Sifive E300 Freedom Core

Hi,
I’ve followed the tutorial found here in loading and running hello world. Everything has built fine, however I’m facing an error (or hang?) when uploading the program.

My terminal shows

Open On-Chip Debugger 0.10.0+dev (SiFive OpenOCD 0.10.0-2019.08.2)
Licensed under GNU GPL v2
For bug reports:
Issues · sifive/freedom-tools · GitHub
adapter speed: 10000 kHz
Info : auto-selecting first available session transport “jtag”. To override use 'transport select '.
Info : ftdi: if you experience problems at higher adapter clocks, try the command “ftdi_tdo_sample_edge falling”
Info : clock speed 10000 kHz
Info : JTAG tap: riscv.cpu tap/device found: 0x20000913 (mfg: 0x489 (SiFive Inc), part: 0x0000, ver: 0x2)
Info : datacount=1 progbufsize=16
Info : Disabling abstract command reads from CSRs.
Info : Examined RISC-V core; found 1 harts
Info : hart 0: XLEN=32, misa=0x40001105
Info : Listening on port 3333 for gdb connections
Info : Found flash device ‘sp s25fl128s’ (ID 0x00182001)
cleared protection for sectors 64 through 255 on flash bank 0
Ready for Remote Connections
Info : Listening on port 6666 for tcl connections
Info : Listening on port 4444 for telnet connections

And stays frozen at that.
Cancelling and running the upload again results in this:

Open On-Chip Debugger 0.10.0+dev (SiFive OpenOCD 0.10.0-2019.08.2)
Licensed under GNU GPL v2
For bug reports:

adapter speed: 10000 kHz
Info : auto-selecting first available session transport “jtag”. To override use 'transport select '.
Error: libusb_claim_interface() failed with LIBUSB_ERROR_BUSY
Error: unable to open ftdi device with vid 15ba, pid 002a, description ‘Olimex OpenOCD JTAG ARM-USB-TINY-H’, serial ‘’ at bus location '

And disconnecting the USB causes an endless loop of the following errors:

Error: libusb_handle_events() failed with LIBUSB_ERROR_NO_DEVICE
Error: unable to purge ftdi rx buffers: LIBUSB_ERROR_NO_DEVICE
Error: error while flushing MPSSE queue: -4
Error: dmi_scan failed jtag scan
Error: failed read at 0x11, status=2

I would appreciate any assistance offered.
Thanks in advance.