Google Drive link with Arduino firmware used in this project:
https://drive.google.com/drive/folders/0B4YXWiqYWB99UmRYQi1qdXJIVFk?resourcekey=0-dqXf8rrfVykfI9H53piG9A&usp=sharing
I bought the Waveshare devices on Aliexpress: https://www.aliexpress.com/item/400x300-4-2inch-E-Ink-display-module-SPI-Without-backlight-Compatible-with-variuous-board-Ultra-low/32827172081.html
Datasheet with the 42-byte LUT format used in the 4.2" display, but not the exact correct part.
https://www.smart-prototyping.com/image/data/9_Modules/EinkDisplay/GDEW0154T8/IL0373.pdf
Interesting thread with other folks experimenting with LUTs on the 2.7" display.
https://github.com/olikraus/u8g2/issues/318
Waveshare (distributor) datasheet
https://www.waveshare.com/w/upload/6/6a/4.2inch-e-paper-specification.pdf
Good Display (manufacturer) datasheet
http://www.good-display.com/products_detail/productId=321.html
Waveform "theory" with class 7-5-7 pulse sequence:
http://www.multicomponent.se/sub_group_files/13dae3f428be3929dc13fed1f79c5e40.pdf
My favorite microcontroller dev board, the Teensy: https://www.pjrc.com/teensy/
The new awesome 5-series oscilloscope from Tek: https://www.tek.com/oscilloscope/5-series-mso-mixed-signal-oscilloscope