The reMarkable is a pretty hackable eink device.
The RM1 was pretty well modded, but the RM2 is currently somewhat stuck due to a missing frame buffer driver. Some good people are working hard on it though and it seems like it’ll be solved fairly soon. [0]
[1] https://support.remarkable.com/hc/en-us/articles/36000264593...
plus ça change, plus c’est la même chose.