Hi.
I just spend 2 days debugging problem with dfu. In the function nrf_dfu_app_continue the function nrf_dfu_flash_store is called with len parmeter as bytes and should be words (is 4096 should be 1024). It caused invalidating my data in bank as I used dual bank for small application - smaller than 16kb.
I am working on sdk 12.0 but I checked and in sdk 14.0 this bug is still present.
Best regards, Michal