I’m assuming this is the Marshmallow update.
I used the self updater and the phone burned through 70% of battery within an hour while booting and optimizing/recompiling the apps again and again.
I’ll try later to apply a fresh flash so be warned this might not work as intended!
important: BEFORE RUNNING THE OTA YOU MUST BACK UP!
there is a major chance you will have to factory wipe your phone!