The latest Android BSP that supported the i.MX6SL EPD is Android Ice Cream Sandwich (R13.5).
That being said it should be possible to use the EPD on Android Kit Kat as Linux does support it. One option would be to disable all other display support in Kernel so it would be forced to use the EPD.
Another option would be to set the boot arguments to choose the EPD. Unfortunately there is no much information on this as it’s no longer supported but you may find some on the release documents from ICS. Taking these ICS documents as reference it would look something like:
bootargs=console=ttymxc0,115200 init=/init max17135:pass=2,vcom=-2030000 video=mxcepdcfb:E060SCM,bpp=16 androidboot.console=ttymxc0 androidboot.hardware=freescale csi
I hope this information helps. Please let us know of your progress in this regard!