UPDATE: SuperSU-v1.55 added the fix for the OTA update issue, so this post is no longer necessary unless you are using an older version of SuperSU
This post also applies to JSS15Q update.
I actually went through and tested JWR66N rooted with SuperSU and the JSS15J OTA update. I expected it to work but it exited with an error.
Ironically the JSS15J OTA actually did patch every single file successfully but near the end while setting permissions, it came up with an error, so after reboot you'll actually be running with all JSS15J rom files, except your build will still say JWR66N, you'll still be running the JWR66N recovery, and you'll still be running the 3.05 bootloader.
I tracked down the issue and put together a fix for it. If you want, it is attached to this post. You just run it after installing SuperSU, so basically:
- adb reboot bootloader
- fastboot boot twrp.img
You'll need to redo these steps (both the installs) after you receive the OTA to preserve root and ability to receive future OTAs.
Also as others have mentioned it is best to be running stock recovery (which the above commands will allow you to do because twrp is never flashed on the tablet) I've attached the stock recovery for JSS15J in case someone needs it.
If you make ANY modifications or delete files from the stock ROM with your new root privileges, then you will greatly increase the chances of the OTA failing. Adding new files is normally fine.