They fixed it!!!! They went and fixed it!!!!!
KOReader sync is now working with CrossPoint on the #Xteink. 🤩
Version 1.3.0 is what you want. I didn't manage to use the OTA update, although apparently they improved that too for the future. I just went and flashed the latest version with the web flasher. As the settings and books are stored on the SD card, you don't lose anything.