iFixit has done a teardown of the new Apple HomePod and here's the conclusion upfront: it's not meant to be opened by the consumer. So pretty much like most consumer electronics these days. End of story. If you are still curious, this is how it goes down. You first need a heat gun to get through to the screen at the top and the rubber base at the bottom, which are securely fastened with glue. Then after that you find some more screws, then some more glue, then some more screws, then some more glue. At one point, iFixit even managed to crack their HomePod while trying to get through a glued...
Source: https://www.gsmarena.com/ifixit_does_a_teardown_of_the_new_apple_homepod-news-29598.php
