assert flash Memory Metadata not aligned after FOTA

[Simsim]

Hi There

I run a NRF52840 with the MESH SDK, and use the Flash manager provided.

After some time i would like to update the Device over FOTA this ends in a Assert on booting with the new firmware at the point flash_manager.c Line 256

NRF_MESH_ASSERT(p_manager->config.p_area[i].metadata.pages_in_area == p_manager->config.page_count);

when erase the full mcu this assert is not showing up due no existing data.

In the best case i can keep the data in the Fields, when not how to erase the Flash bevore or at the FOTA?

Regards Simon

[Susheel Nuguru]

It seems like it has happened before like in this thread and here.

In this thread, even though the same assert happens, it seems like the user had success when they use smaller values of ACCESS_ELEMENT_COUNT and ACCESS_MODEL_COUNT.

[Simsim]

Hi Susheel

thanks for the links, they mostly recomend the --eraseall while programming over jlink.

ACCESS_ELEMENT_COUNT and ACCESS_MODEL_COUNT only have an influence on the first Flash Manager controlled by the mesh_stack and shift the flash layout when changed what not happend in this case.

I found many beginners struggling when loading different exampels without --eraseall of the mcu the get stuck in the asserts. 

I would like to build a software version which can be uploaded over FOTA with a partial blank flash sector or check the nvmc for a flash config id which i can compare with my actual if it match i will proceed, otherwise i had to erase all the flash to ensure the data integrity.

mesh_stack_config_clear() is alredy implemented and working as expected.

while taking the mesh_stack_config_clear() as sample, there i discovered that the entry will be first overwritten and then cleared, otherwise i will find the metadata of the depreciated flash entry and assume the flash is valid?

The assert i could reproduce is when the pagecount is increased so that the memory layout will be shiftedfor the following entries.

Code line 10 assert at flash_manager.c line 256

static bool flash_area_is_valid(const flash_manager_t * p_manager)
{
    for (uint32_t i = 0; i < p_manager->config.page_count; i++)
    {
        if (metadata_is_valid(&p_manager->config.p_area[i].metadata))
        {
            /* Check that the existing metadata aligns with ours */
            NRF_MESH_ASSERT(p_manager->config.p_area[i].metadata.page_index == i);
            __LOG(LOG_SRC_APP, LOG_LEVEL_INFO, "check meta data: %x versus %x \n",p_manager->config.p_area[i].metadata.pages_in_area, p_manager->config.page_count);
            NRF_MESH_ASSERT(p_manager->config.p_area[i].metadata.pages_in_area == p_manager->config.page_count); // assert when structure is different
        }
        else
        {
            return false;
        }
    }

    return true;
}

<t:      10980>, flash_manager_defrag.c,  630, BOOTLOADERADDR(): 0xFFFFFFFF fm_recovery_area: 0x000FF000
<t:      10993>, flash_manager.c,  826, FM area: 0x000FE000
<t:      10996>, flash_manager.c,  256, check meta data: 1 versus 1 
<t:      11000>, flash_manager.c,  826, FM area: 0x000FC000
<t:      11003>, flash_manager.c,  256, check meta data: 1 versus 2 
<t:      11006>, app_error_weak.c,  105, Mesh assert at 0x00035C60 (:0)

Can you short summarise how to erase properly the user flash  entries/pages (without knowing the old layout).

Regards

Simon