Full modem update problems

[Christian77]

Hello.

I'm using nrf9151 with nRF Connect SDK v3.1.1 and Zephyr v4.1.99, modem firmware v2.0.2
I try to implement the full modem update. After downloading the "firmware.update.image_2.0.1.cbor" file from Thingsboard server via CoAP, I'm writing it to external flash. I also check the hash value by reading back from extern flash and it is correct. After that I disconnect from LTE network and try to call nrf_modem_lib_shutdown(), nrf_modem_lib_bootloader_init() and fmfu_fdev_load().

    int err;

    LOG_INF("Disconnecting from LTE network");
    err = lte_lc_offline();
    if (err)
    {
        LOG_ERR("Failed to disconnect from LTE network, error: %d", err);
        return err;
    }
    k_msleep(10000);

    err = nrf_modem_lib_shutdown();
    if (err != 0)
    {
        LOG_ERR("Modem shutdown failed: %d.", err);
        return err;
    }
    k_msleep(10000);

    err = nrf_modem_lib_bootloader_init();
    if (err != 0)
    {
        LOG_ERR("nrf_modem_lib_bootloader_init() failed: %d.", err);
        return err;
    }
    k_msleep(10000);

    err = fmfu_fdev_load(fmfu_buf, buf_len, flash_dev, 0);
    if (err != 0)
    {
        LOG_ERR("fmfu_fdev_load failed: %d.", err);
        nrf_modem_lib_shutdown();
        return err;
    }

    err = nrf_modem_lib_shutdown();
    if (err != 0)
    {
        LOG_ERR("nrf_modem_lib_shutdown() failed: %d.", err);
        return err;
    }

The problem is, that sometimes the call to nrf_modem_lib_bootloader_init() fails with error -116. Sometimes it works but then fmfu_fdev_load() fails with error (-22 - Unable to decode wrapper). 

What I'm doing wrong?

Thanks and BR
Christian

[Benjamin]

Hi Christian,

You mentioned this happens sometimes. How often does it occur? Have you noticed any pattern in when it works and when it does not?

Is this based on the sample, if yes, what have you changed?

Regards,
Benjamin

[Christian77]

Hello Benjamin.

No, I can't say what is different when it works, sorry.

It's based on the "modem_full_update" sample. But I only copied the part for updating and not for downloading to my custom application. So it's very different to the sample.

BR
Christian