The firmware Increment meets the Definition of Done and is fully usable at Sprint Review, but the Product Owner decides not to release it to customers yet because a hardware certification cycle hasn't completed. Does this delay mean the Increment isn't real yet?

The Guide separates two things that are easy to conflate: an Increment exists once it meets the Definition of Done and is usable, while the decision to actually release it to customers belongs to the Product Owner and can be delayed for business or regulatory reasons without undoing the Increment's existence. Nestbot's firmware team meeting the Definition of Done and being usable at Sprint Review means the Increment is real regardless of the pending certification cycle. Claiming the Increment only exists once released collapses two separate concepts into one and would mean regulated products with mandatory gates, like hardware certification, could never produce an Increment until launch, which isn't how the framework works. Assuming certification gates are automatically part of the Definition of Done overreaches; they may be included if the team chooses, but nothing makes that automatic, and here the Increment already meets the Done standard the team actually holds. Saying it's not yet real, but only because Sprint Review is a release event, gets the mechanism backwards, since Sprint Review is where the Increment is inspected, not where release is decided. A concrete check for Nestbot: keep the "is it Done" conversation with the Developers separate from the "should we ship it now" conversation the Product Owner owns.