[eddie.t.h]

Hello. I had the same problem as you. I solved it maybe a little not elegant but important that it works. You must set the vcom voltage for this display. Try the "echo 125 > /sys/devices/platform/eink_fb.0/vcom" command. This will mean the vcom -1,25V voltage. You need to experiment with the values until you get the right effect.
The effect is immediate. Just switch pages of some book and see if it's ok. Once I got the right value, I just added this command to the file /etc/rcS.d/S10filesystems just before exit 0.
A much better solution is resolder eeprom from the original display. If you do reset to factory on the Chinese chip, your Kindle will get the bootloop because there is no data for waveform.

Good luck...