Nexus 9 LTE variant running stock MOB30M ROM here.
Installing version 4.14 results in a bootloop.
My install steps are:
1. Flash the stock MOB30M boot.img via fastboot.
2. Boot directly into recovery (TWRP 3.0.2-0).
3. Install SuperSU 2.65 stable.
4. Install the ElementalX 4.14 kernel ZIP file.
5. Reboot.
I even flashed the stock system.img and vendor.img to be sure.
One thing I noticed that even the stock Google kernel patched with FED Patcher won't boot.
The only kernel that boots is FIRE-ICE. I'm coming from USBHost's FIRE-ICE kernel, if that matters.
Is there a special step I'm missing? I installed ElementalX 1.18 on my Nexus 6P using the same exact steps and it's working fine there.
EDIT: Figured it out. Erased the data partition in fastboot, then formatted it in TWRP, and the tablet finally booted with ElementalX installed.