Does the ESP32 OTA process support resuming transmission after power failure?

[chaoaaaa]

Does the OTA process of ESP32S3 support saving the flashing progress, and can it resume the OTA process from the previous position after power-off and restart?

For example, if there are 20 frames of OTA data to be transmitted, and 10 frames of data have been transmitted and flashed successfully through the esp_ota_write() function, can ESP32 start transmitting from the 11th frame after restarting and continue the OTA process?

[hmalpani]

Hello @chaoaaaa
At the moment, the OTA resumption across reboots/power-off is not supported in ESP-IDF. However, I want to assure you that it's in our plans, and we will have it implemented it in near future.

[a.bernasconi]

I see that OTA resumption is available in esp-idf v5.5.1, however, I've also noticed this in the standard esp_https_ota function:

Code: Select all

if (ota_config->ota_resumption) {
        ESP_LOGE(TAG, "OTA resumption is not supported in esp_https_ota API");
        return ESP_ERR_NOT_SUPPORTED;
    }

What is the reason for this?
Is it safe to use the OTA resumption feature (in our custom OTA routine).

[a.bernasconi]

@hmalpani Any remarks?
As far as I can tell from my tests, OTA resumption works on v5.5.1. I have tried with both partial http download enabled and without, and haven't found any issues yet.
Are there any caveats I should consider?