[Q] Restore Xperia Z2 Tablet to Factory topic

I rooted and installed Cyanygenmod 11 on my Xperia Z2 tablet (SGP512) after making a backup of my ROM.
I now want to restore the factory rom, but when I do that the tablet reboots infinitely.
I tried using the Sony Emma tool but it doesn't seem to recognize my device.
I am back to CM11.
Any thoughts on how I can get back to factory state?