Hey Rst, first, thank you very much for your work on this and Circle. If you ever wonder if people actually try these things out, we definitely do!
I am having an issue with your uspi samples. Ive tried the keyboard and others, but I only get a blank screen. Pressing keys does nothing as well. I made sure to get the latest boot files from the link you provided in the git page. Replacing the kernal.img with a different one for my own project works fine. Might there be specific config file settings that needs to be set for this to boot? Also, no rainbow screen and my monitor indicates that it has a signal, so it just appears nothing is happening. I also get this same behavior compiling and running Circle. My setup is the yargato toolchain on Windows, which seems to be working on with other projects.