K4 (Kindle 4 non-touch) and K5 (Kindle touch) use the framebuffer in a different way than the K3 and earlier devices.
Unlike K3 and older which default to 4 bits/pixel, the new K4 and Touch use 8 bits/pixel.
Where the K3 and earlier 6-inch screen models used 300 bytes/row in 600x800 portrait mode, the K4 uses 600 bytes/row, and the Touch uses 608 bytes/row (8 bytes of padding past the last column).
Newer framebuffer code will need to take stride (byte distance between pixel rows) into account (300, 600, or 608). In addition, these will change for landscape modes for all devices.
*** Another problem is that the Touch is not responding to sending update commands using ioctl (which works fine on the K4). I only see that the framebuffer changed when some external event causes a display update.
And not only is the Touch ioctl call not doing display updates, but my Touch also does NOT have /proc/eink_fb/update_display used by scripts and by some native programs to trigger display updates.
Another interesting thing is that the touch has more than twice as many "virtual lines" as it needs. Perhaps the framebuffer contains two screens full of data (double buffered?). I need to study some of the GPL code to figure this out.
At least the K4 is still mostly compatible with the old-style framebuffer control used by many hacks.
The touch will require further investigation.
Here are the eink settings reported by framebuffer ioctl for my kindles:
Touch (a/k/a KT or K5):
I do not yet have a K2 or K1, but I would really like to get them for testing. Does anybody have an old one no longer loved, neglected in a drawer, on a shelf, in a closet, or under a bed (or packed away in a box)? I am sure it would love a new home where it will get plenty of attention.