Google already announced that it would release Android 6.0 Marshmallow today, and it looks like the company wants to keep it’s word. The factory images of the new version are now available for the Nexus devices that are supported. The images are up on Google’s specialized developer website, where you can also find instructions for flashing them. Keep in mind however that going this route will wipe all the data on your phone or tablet, so make sure you take a backup first.
The images are now available for LG Nexus 5, Motorola Nexus 6, Asus Nexus 7 (2013), HTC Nexus 9, and Asus Nexus Player. Older Nexus devices are not going to get official updates to Marshmallow, while the newly announced LG Nexus 5X and Huawei Nexus 6P have it preinstalled. You may expect OTA’s to start rolling out for the above mentioned devices within the next few hours, it will however depend on Region, Carriers and Device Models. The official OTA is the best way to go if you don’t want to loose your data and go through the hassle, unlike most Nexus owners.
UPDATE : OTA’s will be making their way today itself according to Google’s Official Blog