audioOS 9.9.15.5.1 (build 19L580) is an official Apple over-the-air update for the HomePod, released on 2022-05-25T17:16:55Z. The update package is 468.24 MB. This is a delta (partial) update that requires 15.2 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: f3bf86fe91b89bb5701c23a1c73cc2823b5c5832.zip.