So, I have on older install of Raspbian on my Pi 3B that I decided to upgrade. (Well, replace is a better word.) It’s been driving my Unicorn Hat forever and has had zero issues. But my new install of Stretch can’t seem to get the Unicorn Hat to work at all. Some of the examples will light up a couple pixels in the corner, but that’s it. If I go back to my old install, works like a charm all over again. (So, I know the Unicorn Hat is fine.)
I’ve tried everything I can think of to ensure that audio is going out over HDMI and not the 3.5 jack. (And it is going out over HDMI, sound plays just fine.)
Am I stuck without my Unicorn Hat when using Stretch? Or is there some configuration issue I’m not ware of? Thanks for any help you can offer!
When you ran the installer, were you presented with the options about sound output? Typically the most common issue with unicorn hats is to do with the sound settings as the pins are shared/repurposed to allow neopixel matrix control.
Ran this command to setup:
curl https://get.pimoroni.com/unicornhat | bash
It didn’t really present me with any options other than “are you sure?”. Installer completed just fine and code examples execute without errors. I have been focusing my troubleshooting efforts around sound as that seems to be the root cause of most issues.
I think I’m going to try setting up a fresh image with CLI only and see if I can get it working… hopefully I can have both sound over HDMI and my Unicorn Hat running at the same time.
So, it looks like the reason I never got prompted for this during install was that my config.txt already contained the “hdmi_force_hotplug=1” setting. I just performed the install on a fresh raspbian lite and the Unicorn Hat works as expected. This definitely has something to do with audio…
I just stumbled across this forum post:
Unicorn pHAT - incompatible with Retropie?
My raspbian install that doesn’t work is a RetroPie image. I double-checked the analog jack and there is no sound coming out, it’s only going over HDMI… Let’s see if I can close in on a solution.