SDK 15.3 Add custom DFU settings fails

[Jefferson]

I want to save encryption state in DFU to the nrf_dfu_settings_t structure.  I put a new 16-byte field at the end of the structure after nrf_dfu_adv_name_t  adv_name; and whenever I restart the bootloader the state is erased.  All the other fields are preserved.  What am I doing wrong?  I print out the value in settings_write() and it is correct before I restart the bootloader.

[Jefferson]

It seems to work if I add my custom field in nrf_dfu_settings_t like this:

uint8_t init_command[INIT_COMMAND_MAX_SIZE - 16]; /**< Buffer for storing the init command. */
uint8_t custom[16];

uint32_t boot_validation_crc;
boot_validation_t boot_validation_softdevice;
boot_validation_t boot_validation_app;
boot_validation_t boot_validation_bootloader;

nrf_dfu_peer_data_t peer_data; /**< Not included in calculated CRC. */
nrf_dfu_adv_name_t adv_name; /**< Not included in calculated CRC. */

It did not work when I added like this:

uint8_t init_command[INIT_COMMAND_MAX_SIZE]; /**< Buffer for storing the init command. */

uint32_t boot_validation_crc;
boot_validation_t boot_validation_softdevice;
boot_validation_t boot_validation_app;
boot_validation_t boot_validation_bootloader;

nrf_dfu_peer_data_t peer_data; /**< Not included in calculated CRC. */
nrf_dfu_adv_name_t adv_name; /**< Not included in calculated CRC. */

uint8_t custom[16];

Is it ok to do it the first way by using the last 16 bytes from the init_command buffer?  I will not be using large init commands.

[Simon]

Hello, I am sorry for the late reply. I don't see any consequences of the modification right away since you are keeping the size (offset) the same, and generating settings page with nrfutil should still work (I think).

However, I don't have a complete overview and can't give you a guarantee that the modification won't cause unwanted behavior.

Best regards,

Simon