[NiLuJe]

Start with a simple hard-shutdown: hold the power button down for *a while* until the device actually turns off.

Will be easier to spot if the frontlight was previously on, as it'll then turn off (you're not in nickel, so seeing a "powered off" screen is never going to happen).

After that, here be dragons, because I don't recall if KSM shortcuts the factory reset process during the boot. And since KSM on the Forma is unsupported and half broken, extra weirdness may ensue.

That said, once it is actually off, powering it on with a page turn button held down *should* do the trick... assuming KSM doesn't break that on the Forma, as I mentioned earlier.

(Checking the power button's LED can help, it'll blink during the boot process. The way it's placed on the Forma is a little akward to do that *while* holding it down, though).

Things may or may not behave better with the device plugged to a power source or completely unplugged. I'd start with unplugged, unless you know the battery's flat.