Last night I did some testing with the latest alpha9 in combination with the Google AIY v1 and was also suprised that at the first boot indeed for some reason the screen stayed black.
SSH-ed into the box and gave it a quick reboot and all was good again. Not sure what it was and was under the impression that perhaps a little “bit” got stuck just for me but now you report the exact same, so will have another look.
My advise, don’t go down in version numbers. Perhaps it is better to do the same as me and just give it a little reboot to see if it comes up. At my dmesg I saw some atomic timing issues related to the HDMI driver, so perhaps the current kernel version wasn’t really perfectly timed. Will check the rpi kernel github repo and if needed bump the kernel and associated drivers to see if it works.
EDIT: Oh crap, I just realised the last alpha9 I build and pushed, was not a clean build after the last kernel and firmware bump
Will bump again, just to be sure and create a clean build. Downside; that will take up to almost 24 hours. Will report back, when the new image is pushed.
(BTW: Google AIY v1 voice HAT, just works with MycroftOS. All it currently needs is the “dtoverlay=googlevoicehat-soundcard” added to config.txt Hope to have it added to the auto detect logic just like the respeaker hats soon)