Bootloader Flashing Error - Nordic NRF52840 USB Dongle

[ashokr.com]

Hi All,

Im trying to flash the pre boot-loader from here github.com/.../releases

to my nordic usb dongle.

hex-> mdk_nrf52840_dongle_bootloader-0.3.2_s140_6.1.1.hex
Im getting the DFU error.
DFU failed: Error message for known extended error code from DFU target: The init packet does not contain a signature. This bootloader requires DFU updates to be signed.

Please help on this.
Ashok R

[Amanda Hsieh]

Hi,

The nRF52840 Dongle comes preprogrammed with the Open Bootloader with DFU, which allows users to update the application firmware. However, as stated in the link above: 

• Bootloader update must come from signed packages.

We do not distribute the private key that the public key in the Open Bootloader uses, so the only way to update the bootloader on the nRF52840 dongle is to re-flash using a JLink programmer or the JLink OB programmer on a nRF52xxx DK. You will then have to solder wires to the SWDCLK and SWDIO pads on the nRF52840 Dongle or solder on a 10-pin programming header to the P1 pads. 

Please be aware that mdk_nrf52840_dongle_bootloader-0.3.2_s140_6.1.1.hex is suitable to MakerDiary NRF52840-MDK USB Dongle. You should flash pca10059_bootloader-0.3.2_s140_6.1.1.hex in your source link. See "Using an external debugger" in the nRF52840 dongle programming tutorial

-Amanda H.