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A/B update

Keeping two app slots and always writing the update into the one that isn't running.

An A/B update scheme writes each new image into the inactive slot and switches the boot selection only after the image is complete, so the running image is never overwritten.

Examples

  • A fan controller running from ota_0 downloads 1.5.0 into ota_1; if the power fails mid-download, ota_0 still boots untouched.

  • Choosing the "Huge APP (No OTA)" scheme gives up the A/B layout, so that device can never update over the air.

See also

app slot otadata bricked atomic write
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