Like last year, Google has released a developer preview for Android O two months before the company’s developer conference. There’s no public over-the-air update this time around, though, so you’ll have to manually flash the system images to your phone.
Google has posted factory images for the Nexus 5X, 6P, Nexus Player, Pixel C, Pixel, and Pixel XL. We should caution, however, that the first developer preview is often the buggiest. There could be bugs that brick your device, so make sure you back up your data before you do anything. Google also mentions that a public beta will be available at a later date, and this first preview is largely for developers. Still, if you want to take a crack at seeing Android O now, we put together this comprehensive guide detailing each and every step of the way.
How to flash the factory image
Flashing the factory image differs from installing the over-the-air (OTA) update in that the factory image contains the full system files for your device, whereas the OTA update contains only the upgrade information. In other words, flashing a factory image is more like completely deleting all the software on your device and replacing it. The OTA will only replace what is being changed since your last update.
Some people prefer to install the OTA update since you don’t have to do a factory reset, while others like the factory image method because it’s like starting from scratch with a fresh install of the entire system. It’s more of a pain to factory reset your device, but you are less prone to some of those annoying bugs that seem to crop up after an OTA update.
Remember to make sure all your data is backed up, because you will lose all your data on the device when you unlock the bootloader, which is required for flashing. There is no way to unlock a bootloader without a factory reset. However, if you happen to already have an unlocked bootloader, then you can forgo the factory reset if you wish. We will show you how later on, but we still recommend that you back up your data in case something goes wrong.