Rollback support for OTA ?

[MarusGradinaru]

Hi !
From what I understand, ESP-IDF has a rollback system for OTA uploads.
That is, after the upload, the partition with the new firmware is marked with the SP_OTA_IMG_PENDING_VERIFY flag, and if at the next boot you do not manually call a function from the code that validates the firmware, the second boot will run the old stable firmware.

I tried OTA upload with ArduinoOTA library and it seems that the old firmware is not rolled back if I restart the device without validating the new one... They say that I must enable this behavior with CONFIG_BOOTLOADER_APP_ROLLBACK_ENABLE. But I don't know where to make that setting. I am working in PlatformIO and I tried to add it in platformio.ini at build_flags =. But it has no effect...

Can you tell me what should I do to enable this rollback option on ESP32 ?

[P-R-O-C-H-Y]

Hi, I see this feature(config) is enabled for all SoCs in our core. I will test to see if its working properly.

[P-R-O-C-H-Y]

@MarusGradinaru I have tested the rollback and it works as expected:

Why build_flags doesn’t work

CONFIG_BOOTLOADER_APP_ROLLBACK_ENABLE is a bootloader Kconfig option. It’s fixed when the bootloader is compiled, not when your app is built. Adding it in platformio.ini / build_flags only affects the app, so it has no effect on rollback.

What actually enables rollback

Rollback is enabled only if the bootloader was built with that option. In the official Arduino-ESP32 core the default sdkconfig already has CONFIG_BOOTLOADER_APP_ROLLBACK_ENABLE=y and CONFIG_APP_ROLLBACK_ENABLE=y, so rollback is on by default when you use that core and its bootloader.

If rollback doesn’t happen, check:

• Partition table – You need two OTA app slots (e.g. ota_0 / ota_1 or app0 / app1) and an otadata partition. A single-app or “minimal” table without otadata can’t do rollback.

• PlatformIO / framework – You may be using a prebuilt bootloader that was built without rollback. Then you need a framework/build that ships a bootloader compiled with rollback enabled (as the official Arduino-ESP32 core does), or you have to build and flash your own bootloader with CONFIG_BOOTLOADER_APP_ROLLBACK_ENABLE=y in sdkconfig.

You can’t enable rollback from platformio.ini; it’s decided by the bootloader build. Use an OTA partition table (two app slots + otadata) and a framework/core that provides a rollback-enabled bootloader (e.g. official Arduino-ESP32).

If you want, I can send you examples to verify if rollback feature works for your setup.

[MarusGradinaru]

Thanks for the replay !

I recently entered this world of ESP32, and I don't think I fully understand how everything works around here... I started with VS Code with Platform IO and Arduino framework. But, at some point, I discovered that my system was reporting an older version of the Arduino framework and ESP-IDF. Obviously I wanted to use a newer version as well. And after much searching, the only solution was to replace PlatformIO with pioarduino, which uses newer versions of the Arduino framework. But now, I don't understand what framework I'm actually using... In my platformio.ini I have this:

[env:esp32dev]
platform = https://github.com/pioarduino/platform-espressif32/releases/download/stable/platform-espressif32.zip
board = esp32dev
framework = arduino

And when I build my program it show like this:

PLATFORM: Espressif 32 (55.3.32) > Espressif ESP32 Dev Module
PACKAGES:
 - contrib-piohome @ 3.4.4
 - framework-arduinoespressif32 @ 3.3.2
 - framework-arduinoespressif32-libs @ 5.5.0+sha.07e9bf4970
 - tool-esptoolpy @ 5.1.0
 - tool-mklittlefs @ 3.2.0
 - tool-openocd-esp32 @ 2.1200.20250707 (12.0)
 - tool-xtensa-esp-elf-gdb @ 16.3.0+20250913
 - toolchain-xtensa-esp-elf @ 14.2.0+20250730

So I don't know for sure if I use that bootloader that you said it has rollback option enabled, or other who doesn't... The pioarduino seems to be a fork from this library. Shouldn't it have the same bootloader ?

[P-R-O-C-H-Y]

@Jason2866 Can you please help here? Thanks

[Jason2866]

@MarusGradinaru to update to latest pin the version. Use this

[env:esp32dev]
platform = https://github.com/pioarduino/platform-espressif32/releases/download/55.03.37/platform-espressif32.zip
board = esp32dev
framework = arduino

It uses the original libs from release section of this repo. If the feature works with ArduinoIDE it will work with pioarduino too.

[RomanAlexandroff]

@MarusGradinaru, you absolutely can use the ESP32 bootloader-level rollback in Arduino IDE. @P-R-O-C-H-Y was right that in the official Arduino-ESP32 core bootloader is already rollback-enabled by default.

The issue why firmware rollbacks do not work straight away is again Arduino. By default, Arduino auto-validates all the firmware that gets uploaded to your ESP32, so whenever you check your firmware status it always says ESP_OTA_IMG_VALID. Why? Probably because it saves the beginners from the confusion why their firmware suddenly changes on the fly.

The fix is very easy: just copy-paste the following function as-is to your code global scope - somewhere so it runs before setup() - and that's literally it. That deactivates the Arduino auto-validation and now you can use the bootloader's rollback feature.

extern "C" bool verifyRollbackLater(void)
{
    return true;
}

[MarusGradinaru]

That's great news !
But I don't use Arduino IDE. I work in VSCode with Platform IO. Is it the same here ?

[RomanAlexandroff]

I believe that PlatformIO uses the very same Arduino-ESP32 core instead of ESP-IDF... Long story short, it should work for PlatformIO too.

If you try it with PlatformIO, please, let us know the results =)

[MarusGradinaru]

Ok, I'll try it and let you know... But it will take some time to reconstruct the setup, as now I'm working on other projects...
In my VSCode PlatformIO, I always use the Arduino framework, not ESP-IDF. I gues this means your fix will work here too ?