Valid DFU ZIP containing a new bootloader, nRF52

[Dan Danknick]

I am running SDK12.3 on an nRF52 and the bootloader on my boards has no problem replacing the application through the DFU process. Now I found a mistake in the bootloader itself so I need to replace it. My build script for the replacement bootloader package is:

nrfutil pkg generate --hw-version 52 --sd-req 0x8C --bootloader-version 2 --bootloader nrf52832_s132_DFU.hex --key-file ..\DFBP_private.pem DFBP_dfu_BL_package.zip

nrfutil does not complain. But when I try to send it over either by iOS through nRF Toolbox on Windows through nRF Connect 2.0.0 it quickly fails. nRF Connect helpfully supplies "ERROR When writing 'EXECUTE' command to Control Point Characteristic of DFU Target: Operation code 4 (EXECUTE) failed on DFU Target. Result code 10 (OPERATION_FAILED)."

Anyone have a tip on how to fix this?

Thanks, Dan

[Dan Danknick]

Bjørn, the existing bootloader on my device was also "--bootloader-version 2" so changing my script to "--bootloader-version 3" created a .zip that transferred perfectly. Thank you for your help!

[bjorn-spockeli]

Happy to help!