RE: 52840 DFU operational failure/question

JMF — Thu, 24 Oct 2019 19:08:25 GMT

Thank you that was what I needed to know!

RE: 52840 DFU operational failure/question

bjorn-spockeli — Thu, 24 Oct 2019 10:56:01 GMT

Hi, you can add it as an additional load file, i.e. it is loaded after the bootloader when you click download in SES. You can add it by right-clicking Project in the Project explorer, then Options, select Common in the drop-down menu in the upper-left corner. Then navigate to Debug > Loader > Additional Load File[0] and browse to <SDK folder>\components\softdevice\s140\hex to find the SoftDevice hex.

Optionally you can flash the SoftDevice using nrfjprog with the following command:

nrfjprog --program s140_nrf52_7.0.1_softdevice.hex --sectorerase --reset

Best regards

Bjørn

RE: 52840 DFU operational failure/question

JMF — Wed, 23 Oct 2019 13:35:31 GMT

Bjorn, thank you for the response. I am using the SEGGER Embedded Stdio, can you possible tell me how do I add the SD to the bootloader so that when it downloads, it includes the SD? Also, is there anyway to tell the DFU SW to ignore the presence of a SD and simply program the one that is provided?

RE: 52840 DFU operational failure/question

bjorn-spockeli — Wed, 23 Oct 2019 11:45:24 GMT

Hi JMF,

if you take a look at the sd_req_ok() in nrf_dfu_ver_validation.c

static bool sd_req_ok(dfu_init_command_t const * p_init)
{
    ASSERT(p_init != NULL);
    bool result;
#if defined(BLE_STACK_SUPPORT_REQD) || defined(ANT_STACK_SUPPORT_REQD)
    // The bootloader needs the SoftDevice, so disabling NRF_DFU_APP_DOWNGRADE_PREVENTION
    // should not be applied to SoftDevice updates.
    const bool prevent_downgrade = NRF_DFU_APP_DOWNGRADE_PREVENTION || (p_init->type == DFU_FW_TYPE_SOFTDEVICE);
#else
    const bool prevent_downgrade = NRF_DFU_APP_DOWNGRADE_PREVENTION;
#endif

    if (SD_PRESENT)
    {
        if (p_init->sd_req_count == 0)
        {
            result = false;
        }
        else if (p_init->sd_req[0] != SD_REQ_APP_OVERWRITES_SD)
        {
            result = sd_req_check(p_init->sd_req,
                                  p_init->sd_req_count,
                                  (p_init->type == DFU_FW_TYPE_EXTERNAL_APPLICATION));
        }
        else if (p_init->type == DFU_FW_TYPE_APPLICATION)
        {
            // The application wants to overwrite the SoftDevice.
            if (prevent_downgrade && (p_init->sd_req_count > 1) && (p_init->sd_req[0] == SD_REQ_APP_OVERWRITES_SD))
            {
                // The application can overwrite the SD if sd_req[0] == 0 and table has the FWID of the current SD.
                result = sd_req_check(p_init->sd_req, p_init->sd_req_count, false);

                // Prevent BLE bootloaders from allowing applications overwriting the SoftDevice.
#ifdef BLE_STACK_SUPPORT_REQD
                result = false;
#endif // BLE_STACK_SUPPORT_REQD
            }
            else
            {
                result = true;
            }
        }
#if NRF_DFU_SUPPORTS_EXTERNAL_APP
        else if(p_init->type == DFU_FW_TYPE_EXTERNAL_APPLICATION)
        {
            // Won't accept FW upgrade using external application to
            // enforce replacing SoftDevice (SD_REQ_APP_OVERWRITES_SD)
            result = false;
        }
#endif // NRF_DFU_SUPPORTS_EXTERNAL_APP
        else
        {
            // Don't allow SoftDevice updates which assume no SD is present already.
            result = !prevent_downgrade || (p_init->type != DFU_FW_TYPE_SOFTDEVICE);
        }
    }

    else
    {
        if (p_init->sd_req_count && (p_init->sd_req[0] != SD_REQ_APP_OVERWRITES_SD))
        {
            // Fail if there is no SD and the update requires SD. The special "any" FWID is valid
            // for external apps only.
            result = false;
#if NRF_DFU_SUPPORTS_EXTERNAL_APP
            result = sd_req_check(p_init->sd_req,
                                  p_init->sd_req_count,
                                  (p_init->type == DFU_FW_TYPE_EXTERNAL_APPLICATION));
#endif // NRF_DFU_SUPPORTS_EXTERNAL_APP
        }
        else
        {
            // If there is no SD and update has SD it is accepted only if it has a fw_version.
            result = !prevent_downgrade || p_init->has_fw_version;
        }
    }
    return result;
}

Then you'll see that the bootloader does not allow SoftDevice updates if there are no SD already present on the nRF device. So you will have to flash a SoftDevice together with the Bootloader eventhough the Bootloader does not require the SD.

Best regards

Bjørn