The public and private keys where set.
<info> nrf_sdh: Inside main
<debug> nrf_sdh: In nrf_bootloader_init
<debug> nrf_sdh: in weak nrf_dfu_init_user
<debug> nrf_sdh: In real nrf_dfu_init
<debug> nrf_sdh_soc: Running nrf_dfu_settings_init(sd_irq_initialized=false).
<debug> nrf_dfu_settings: Calling nrf_dfu_flash_init(sd_irq_initialized=false)...
<debug> nrf_dfu_settings: Initializing nrf_fstorage_nvmc backend.
<debug> nrf_sdh: Initializing the clock.
<debug> nrf_sdh: Enter nrf_dfu_continue
<error> nrf_sdh: Single: Invalid bank
<debug> nrf_sdh: Enter nrf_dfu_app_is_valid
<debug> nrf_sdh: Return false in valid app check
<debug> nrf_sdh: In nrf_dfu_transports_init
<debug> nrf_sdh: num transports: 1
<debug> nrf_sdh: UART initialized
<debug> nrf_sdh: After nrf_dfu_transports_init
<debug> nrf_dfu_settings: Calling nrf_dfu_flash_init(sd_irq_initialized=false)...
<debug> nrf_dfu_settings: Initializing nrf_fstorage_nvmc backend.
<debug> nrf_sdh: Waiting for events
<debug> nrf_sdh: Received ping 1
<debug> nrf_sdh: Sending Response: [0x9, 0x1]
<debug> nrf_sdh: Set receipt notif
<debug> nrf_sdh: Sending Response: [0x2, 0x1]
<debug> nrf_sdh: Received get serial mtu
<debug> nrf_sdh: Sending Response: [0x7, 0x1]
[------------------------------------] 0%
Traceback (most recent call last):
File "/usr/local/bin/nrfutil", line 9, in <module>
load_entry_point('nrfutil==3.3.0', 'console_scripts', 'nrfutil')()
File "/Library/Python/2.7/site-packages/click/core.py", line 722, in __call__
return self.main(*args, **kwargs)
File "/Library/Python/2.7/site-packages/click/core.py", line 697, in main
rv = self.invoke(ctx)
File "/Library/Python/2.7/site-packages/click/core.py", line 1066, in invoke
return _process_result(sub_ctx.command.invoke(sub_ctx))
File "/Library/Python/2.7/site-packages/click/core.py", line 1066, in invoke
return _process_result(sub_ctx.command.invoke(sub_ctx))
File "/Library/Python/2.7/site-packages/click/core.py", line 895, in invoke
return ctx.invoke(self.callback, **ctx.params)
File "/Library/Python/2.7/site-packages/click/core.py", line 535, in invoke
return callback(*args, **kwargs)
File "/Library/Python/2.7/site-packages/nrfutil-3.3.0-py2.7.egg/nordicsemi/__main__.py", line 655, in serial
dfu.dfu_send_images()
File "/Library/Python/2.7/site-packages/nrfutil-3.3.0-py2.7.egg/nordicsemi/dfu/dfu.py", line 122, in dfu_send_images
self._dfu_send_image(self.manifest.application)
File "/Library/Python/2.7/site-packages/nrfutil-3.3.0-py2.7.egg/nordicsemi/dfu/dfu.py", line 90, in _dfu_send_image
self.dfu_transport.send_init_packet(data)
File "/Library/Python/2.7/site-packages/nrfutil-3.3.0-py2.7.egg/nordicsemi/dfu/dfu_transport_serial.py", line 239, in send_init_packet
self.__stream_data(data=init_packet)
File "/Library/Python/2.7/site-packages/nrfutil-3.3.0-py2.7.egg/nordicsemi/dfu/dfu_transport_serial.py", line 405, in __stream_data
response = self.__calculate_checksum()
File "/Library/Python/2.7/site-packages/nrfutil-3.3.0-py2.7.egg/nordicsemi/dfu/dfu_transport_serial.py", line 347, in __calculate_checksum
(offset, crc) = struct.unpack('<II', bytearray(response))
TypeError: 'NoneType' object is not iterable
I saw somebody else having the same problem in a comment here, but there was no answer to this specific issue : Nordic Dev Zone