audioOS 9.9.18.1 (build 22J580) is an official Apple over-the-air update for the HomePod (2nd generation), released on 2024-10-28T15:30:27Z. The update package is 1.19 GB. This is a delta (partial) update that requires 17.1.1 already installed. This update is currently signed by Apple, so it can be applied from Settings › General › Software Update.

Payload file: dca6ff9daedf17bc1fbf558dff66487b03b7f1e37040e95fb078e14ad8176367.aea.