PiStorm accelerators come with a video driver for the Raspberry Pi's HDMI output, which, if you're booting CaffeineOS, it uses per default.
If you don't have a HDMI display connected, you're stuck a bit, because you can't just run "Screenmode" preferences program without executing S:Startup-sequence, and deleting ENVARC:sys/screenmode.prefs just resets to HDMI, not PAL (or NTSC).
To temporarily select Amiga native video, you can hold the left shift key while booting.
Now you can run "Screenmode" prefs, and save a PAL (or NTSC) screenmode setting.
To permanently select Amiga native video as default and fallback, you can disable PiStorm's HDMI monitor driver "emu68k-videocore", in directory DEVS:Monitors, by moving it to a different location (e.g. a newly created sub-directory, or SYS:Storage/Monitors).
