Originally Posted by CollinsJ
Thank you Win, that did it. I had to fastboot the CMW as it wouldn't upgrade through recovery, after that I just flashed CM11.
Problem is that due to S-On it is not possible to write to recovery partition from recovery. You also can't write to boot partition, but you can install ROMs without problems if you flash boot image separately through fastboot.
Current device: Oneplus One 64 GB Sandstone Black
No support via PM! Please ask in a public thread, I'll help you as much as I can.