Some info https://hackaday.io/list/35814-e-paper here and especially from the links provided, everyone is working from http://essentialscrap.com/eink/waveforms.html and http://spritesmods.com/?art=einkdisplay

And https://hackaday.io/project/21168-fpga-eink-controller has an FPGA doing waveforms by extracting them from existing firmware. So while it might be a closely guarded secret, just replicating it is possible.