Hey, just want to confirm: The clover boot sound option works great on 2 different systems, an H97M based and a Z370M based system.
As others mentioned "fast" boot setting does not work properly, I set the boot selection time to 0sec, sound works and Clover does not show either!
I did not want the boot chime to show on the regular stereo sound system, I just wanted it on the internal speaker of my Powermac G5 cabinets. So I routed the boot sound to the "non used" 5.1 "rear speaker" line out via the clover selection, added a super small and low cost LM386 amp module into the path to the speaker.
The Z370M board die NOT have the full set of 5.1 analog out sockets, in this case I used the SPDIF digital out of the motherboard, added a 5 euro DAC module, the same LM386 as above and voila boot chime from the internal speaker via SPDIF!
The amp as well as the DAC need 5V supply, which I picked up from an internal USB header.
An extra note for the LM386: they typically come with a 200x gain setting, which is way too high. Remove the bypass network on the module (pin 1 to pin 8 of the IC, R1 on the modules I used) so that the amp runs with internal feedback setting of 20x. Volume adjust will be a lot easier, output static noise will be gone. This is well documented in the application notes for the LM386.