Nope haven’t seen it anywhere in the manual. I read about it somewhere on the internet when I was in desperate straights to get mine out of that stuck in the boot screen mode, but I cannot remember where I saw it. Only happened to me once, and I think it happened because I was experimenting with my own software controlling it over USB. I think I must’ve screwed some parameters up that it tried to load when booting up.
Had the same issue once.
By Keeping the “system” button pressed whilst booting fixed the issue for me.
That is one of the few keys I didn't try
Is it mentioned anywhere in the manual? I looked but didn't see anything.
I'll try to remember it if it ever happens again.