Woohoo! The demo.c included with the tcc kindle package WORKS (after changing "/dev/fb0" to "/dev/fb/0" on one line)! Awesome! It is doing (relatively) fast eink animation on my K1, as I type this message. Because that code (my first C eink animation) made the assumption that each byte was just a fat pixel (and a skinny pixel on a K4 and newer), it "just works" even on the 2-bit K1 framebuffer.
Apparently, ignoring error codes when opening framebuffers (as I do in my demos to simplify the code) leads to segfaults when you write to a bad file descriptor, eh?
The animation is running faster than on a DXG, so perhaps my video player might work okay on the K1 too. I will know soon.
EDIT: I used to launch my eink demos from an SSH terminal, so I could ctrl-C them when I viewed enough. Launched from an install script (or KUAL) takes to long for a quick test (or preview). I suppose I should change my launcher script to launch it in the background, wait for a keypress (or screen touch), then do a killall on the launched script. Makes more sense after waiting too long too many times... ...and I am STILL waiting for "demo" to complete. How long does it run? 