A small bunch of our Android friends who installed Nougat OTA on their Nexus 5X or Nexus 6P while on Developer Preview 5 are experiencing a rather odd issue. The update installs fine, but in next 3-4 hours to 2-3 days, the device reboots and gets stuck into bootloop, at Google splash screen.
That the bootloop occurs after completing the first boot normally, is one of the strangest bugs we’ve heard, ever. But anyway, fix the bootloop by doing this.
You can then try to take Nougat OTA from Marshmallow, and it should work out fine.
It’s said that the Nougat factory image wasn’t working either. So, it’s futile to install NRD90M factory image on Nexus 5X. Though, the recently released NRD90U factory image could already have a fix for this, although Google is yet to confirm whether this has been fixed. Until then, it’s best to go back to Marshmallow using latest Android 6.0.1 factory image, and then look for a system update to come back to Nougat.