audioOS 9.9.12.4 (build 16G78) is an official Apple over-the-air update for the HomePod, released on 2019-07-22T17:29:25Z. The update package is 1.43 GB. This is a delta (partial) update that requires 11.3 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 6ae3234693ab78391e4688bbcd7e84b2cf4e42f5.zip.