Uploading App using Keil uVision on preloaded SD+DFU BL?

RE: Uploading App using Keil uVision on preloaded SD+DFU BL?

Wasil — Fri, 22 Mar 2019 16:31:16 GMT

Thanks Einar. All sorted. Much appreciated.

RE: Uploading App using Keil uVision on preloaded SD+DFU BL?

Einar Thorsrud — Fri, 22 Mar 2019 14:46:52 GMT

Hi,

For SDK 12 this is handled by the nrf_dfu_app_is_valid() function in nrf_dfu_util.c. Just comment out everything related to CRC checking, like this (from 12.3):

bool nrf_dfu_app_is_valid(void)
{
    NRF_LOG_INFO("Enter nrf_dfu_app_is_valid\r\n");
    if (s_dfu_settings.bank_0.bank_code != NRF_DFU_BANK_VALID_APP)
    {
       // Bank 0 has no valid app. Nothing to boot
       NRF_LOG_INFO("Return false in valid app check\r\n");
       return false;
    }

    // If CRC == 0, this means CRC check is skipped.
    // if (s_dfu_settings.bank_0.image_crc != 0)
    // {
    //     uint32_t crc = crc32_compute((uint8_t*) CODE_REGION_1_START,
    //                                  s_dfu_settings.bank_0.image_size,
    //                                  NULL);

    //     if (crc != s_dfu_settings.bank_0.image_crc)
    //     {
    //         // CRC does not match with what is stored.
    //         NRF_LOG_INFO("Return false in CRC\r\n");
    //         return  false;
    //     }
    // }

    NRF_LOG_INFO("Return true. App was valid\r\n");
    return true;
}

RE: Uploading App using Keil uVision on preloaded SD+DFU BL?

Wasil — Fri, 22 Mar 2019 14:36:46 GMT

Hi Einar,

I am using bootloader sdk-v12 and dfu_enter_check() is not in nrf_bootloader.c. Can you point me for disabling CRC on sdk v12? Thanks

RE: Uploading App using Keil uVision on preloaded SD+DFU BL?

Einar Thorsrud — Fri, 22 Mar 2019 09:06:50 GMT

Hi,

The bootloader will check the CRC of the application and compare with the CRC stored in bootloader settings. If the CRC is incorrect, it will enter DFU mode instead of starting the application.

When you modify the application and program it via Keil (or any other method other than DFU for that matter), the CRC in the bootloader settings is not updated, and the bootloader will not start the application. There are a few ways to handle this:

The obvious option is to program the application via DFU, since this causes the bootloader to update the CRC. This works, but is a bit time consuming, so I understand why you want to avoid it.
You can also generate a new bootloader settings page using nrfutil and program it when you program the application. That way the new CRC match the new application.
The simplest (and best in my opinion) approach is to modify the bootloader so that it does not check application CRC on startup. This makes much sense during development. You can do this easily by commenting out the CRC check in dfu_enter_check() in nrf_bootloader.c.