You finally want to update your HomePod from 14.x to 15.x but you get the message: “Could not complete operation”? Then don’t worry, the solution is extremely simple.
There is a bug that prevents HomePod mini from updating if you have the “Sound when using Siri” option set. If you use this setting, the HomePod refuses to import the update.
If you turn this switch off, you can import the latest software version without any further problems – and of course you can also switch the Siri sound back on if you wish.