[NiLuJe]

Well, it certainly works once you add the requisite eInk refreshes, but I didn't look into the calibration format in detail, although it *should* be re-usable across like-minded devices ;p.

There may be some rotation shenanigans to handle to make the automagic rotation correction behave properly (for instance, I had to run the calibration tool without setting the rotation, because of the H2O inverted rotation quirk, otherwise the calibration tool tried to set the current rotation, which ends up throwing us in the inverted one, which means the base rotation stored in the calibration file is wrong, if that matters, which I imagine it might ;p).

Again, that was from a *very* quick test, because I only had a passing interest in seeing how viable that could be. It probably is, just needs a bit more work (and/or check how it deals with gesture detection and the more esoteric variants of the touch protocol).

The calibration tool itself is dead simple: one by one, it shows a cross near the four corners (TL -> TR -> BR -> BL), and then at the center of the screen, and waits for you to tap (ideally, on the cross ;p).