Nrfutil "failed to open" error for DFU over BLE

[Oisin Johnston]

Hi there,

I'm trying to do a DFU over BLE using the Nordic nRF5x SDK on version 14.2. I'm using an NRF51 dongle on the PC side while trying to transmit to an NRF52832, and I'm using one of the example buttonless dfu programs.
Also, my development environment is on linux! Any help with this would be much appreciated! This is the error I get:

[Bjørn Kvaale]

Have you tried to update the application using secure dfu with an easier example first? If you have the nrf52832DK, I can recommend updating the Blinky application first (examples\peripheral\blinky\pca10028\s130). Once the DFU has completed, the LED's 1-4 on the DK should start blinking one after the other. The Buttonless DFU example is essentially the same as described in the Secure DFU blog post, with the exception that after the DFU, the nrf52 should advertise as Nordic_Buttonless. Then, you should be able to connect to the DK via nrf connect on pc or smartphone, write 0x01 to it & notice that the LED's on the DK switch. This signifies that the DK has entered bootloader mode again (see this link to test the buttonless dfu example).