NVS erased after OTA

[erikha]

@martins I've seen that in the changelog of v4.3 as breaking change, but as I interpret that is: it is now enabled by default, but we already enabled that option manually before v4.3 (Component config -> NVS -> Enable NVS encryption). But to be sure, I will investigate this further.

@ESP_rrtandler I added the printf, but the result doesn't tell me much. The error is always 0: `nvs_flash_init() returned: [0x0000]`

[erikha]

Follow-up on the breaking change in v4.3: when I do a read_flash with the esptool of a device that has flash encryption enabled in v4.2, only the partitions labeled "encrypted" are indeed encrypted and the partition labeled "nvs" is not. I expect the breaking change to be that v4.3 will encrypt the partition labeled "nvs" eventhough the partition isn't labeled "encrypted" in partitions.csv.

Can someone from ESP confirm this?

[ESP_rrtandler]

@erikha - The NVS encryption is controlled in a different way than other data partitions encryption.

• Enabled flash encryption ignores the "encrypted" flag for partitions of type=data, subtype=nvs
• If NVS data partition has to be encrypted, the flash encryption (above) has to be enabled, extra partition of type=data, subtype=key and flag encrypted=true has to be added to the partition table. To initialize the encrypted NVS partition, the nvs_flash_secure_init() is called instead nvs_flash_init().

You can refer to the documentations chunks dealing with these differences:

• https://docs.espressif.com/projects/esp ... pted-flash
• https://docs.espressif.com/projects/esp ... encryption

[erikha]

I've found a solution that works for me.

Since v4.3 the function nvs_flash_init() does use the function nvs_flash_secure_init_partition() when nvs encryption is enabled via menuconfig. When this nvs encryption isn't enabled via menuconfig, the function nvs_flash_init() just returns nvs_flash_init_partition(NVS_DEFAULT_PART_NAME).

This made me think that I could replace the call to nvs_flash_init() with nvs_flash_init_partition(NVS_DEFAULT_PART_NAME) to mitigate the problem, and indeed, it did. I'm now able to initialize the default nvs partition after an update without losing data.

Thank you all for your input.