Secure DFU example and NRF_BL_DFU_ALLOW_UPDATE_FROM_APP

[RVM]

I am looking at the 'sdk_config.h' file provided for the secure dfu example in SDK 17.1.0 under the folder: "\examples\dfu\secure_bootloader\pca10040_s132_ble\config".

Can somebody explain why the default value of the symbol 'NRF_BL_DFU_ALLOW_UPDATE_FROM_APP' is set to a '0'.

Isn't the sole purpose of a 'secure dfu' within the realm of the nRF5 SDK to allow updates from the application?

If not, what is the expected workflow for executing a secure DFU? After all, one only needs a DFU so long as there is an active application running on the device.....

Cheers

RMV

[mrono]

RVM said:

Isn't the sole purpose of a 'secure dfu' within the realm of the nRF5 SDK to allow updates from the application?

RVM said:

If not, what is the expected workflow

The usual workflow for the BLE bootloader is that the application only has a means to jump to the bootloader. And the bootloader does the downloading and updating. The downside of this is that the application is not running during the download.

That "allow update from app" option is there for the cases where the application would download the new firmware during its normal operation. And the bootloader would only verify and move the binary to the correct slot. I believe the bootloader for zigbee operates like this.

[RVM]

Thanks for the explanation.