While one can actually enable a poor man's nightmode on pretty much any device since the K5 [c.f.,
the tail end of this thread], the point is moot, as you indeed cannot JailBreak your device, whichever of the Basics it actually is (
read the fine manual for details, and to fix your Device Info box).
Sidebar: the flash to black is irrelevant to the matter, that's just a way to deal with ghosting on eInk.