Re: mcuboot + dfu-util on nRF52840 not able to update firmware
I was able to get DFU working by itself. See the prj.conf and flashing method of this thread (but remove the bluetooth flags because BT HCI will cause problems with DFU in Zephyr 1.14):
Basically, you need to enable the DFU driver, the flash driver, and the DFU manager.
Also be sure to follow this read me for setting up MCUboot:
I was unable to get MCUboot 1.3 working on the nRF52840, but master (2dc9f8f) worked.