I faced the same issue man. It was a mini heart attack for me.Well, I had a critical failure the other night. My phone freaked out, the display went dark, and I couldn't even get it to reboot itself by holding down the power button, nor with power+vol up+vol dwn, nor any other combo. I eventually had to hook up to a computer and then ADB reboot was able to get me back up and running. This was the 2nd time this has happened to me on Nameless ROM.
... and I just cannot have that. If I had been away from the house and needed to call 911, I'd have been screwed.
So .. I'm sorry, but it's back to OOS12 / rooted for me.
However, for those looking to do the upgrade, I suggest using FolderSync to back up your /storage/emulated/0 to somewhere off your device. It's easy to set up and restore, and you can schedule nightly backups of all your stuff. It only syncs what has changed, so after the initial dump, it's pretty quick. That way you can wipe your device and get all your stuff back after installing the new ROM.
Good luck, and thanks for all the hard work, devs.
Then, I flash latest orange fox recovery instead of the one given with rom, side load the rom and everything is fine then. I think there is a problem with the recovery.