There is a relatively-new operating system called “Barbara IoT”, based out of Madrid Spain, which is new to my daily “Verified Boot” searches.
Their security page mentions “verified boot”. Given the vagueness of their web site, I can’t say if this is Linux/Android/Chrome Verified Boot or something else. Unclear what flavor(s) of platform firmware the OS interacts with.
“Raise the security level of your devices with verified boot, data encryption and no exposed network services”
Have not found the source to the OS yet, I’m guessing closed-source. Their web site is pretty closed: it requires you to submit name/email contact info to view any data on their OS. Their home page link to their Developers page is broken.
“Raise the security level of your devices with verified boot,”
Firmware Security 