First Boot After OTA Is Still a Transaction

A successful flash write does not prove the new image can initialize hardware, load state and stay healthy.

I keep this as a field note because the failure mode is easy to misclassify: update success is declared before the new image has run. The useful move is to identify the boundary first, then change only the layer that owns it.

What I model

The system is easier to debug when intent, observation and transport are not collapsed into one state. For this case, my rule is simple: Do not commit the update until the new image proves it can run.

Implementation pattern

Boot the inactive slot as pending, run bounded local validation, then accept or roll back.

I prefer a small explicit contract over a clever implicit one. That gives logs, tests and dashboards something concrete to verify and keeps unrelated layers from compensating for each other.

What I verify

• previous image remains bootable
• failure has deterministic rollback
• fleet distinguishes installed, booted and accepted

Failure handling

When one of those checks fails, I preserve the failing evidence before restarting or changing configuration. The first broken contract determines the next investigation. That keeps troubleshooting causal instead of turning it into a sequence of guesses.

What I keep

Do not commit the update until the new image proves it can run. The specific tools can change, but that ownership boundary remains useful across firmware, networks and infrastructure.