Google has announced the next major version of Android operating system, code-named Android M in its annual I/O conference keynote presentation. Where Lollipop was a massive overhaul of the operating system, both visually and in terms of features, Android M gives more attention on improving the stability and usability of the OS. It does not mean Android M will not have any new feature.
App permissions, Android Pay (mobile payments), Fingerprint reader support, App links, new Power & Charging function known as Doze and Chrome Custom Tabs are the major new features you can expect to see in Android M. Besides that, there are many other features announced during the I/O keynote like the redesigned app drawer, multi-window, etc. Read here.
The first developer preview of Android M system image is now available for Nexus 5, Nexus 6, Nexus 9 and Nexus Player that you can install on your device and see what is new before everyone else getting the OS. However, please note that you will not have full functionality right now. Read on to know how to install Android M on your Nexus 5, Nexus 6 and Nexus 9.
How to Install Android M Developer Preview on Nexus 5, 6 and 9
Warning: As the below procedure wipes your device completely, backup any important data before you start, so that you do not lose anything.
1. It requires ADB and fastboot tools on your computer. The easiest way to install these, download the Developer toolkit [HERE] and install it.
2. Download Android M preview for your Nexus 5/Nexus 6/Nexus 9, unzip the .tar.gz file and save the contents in the ADB Tools folder (platform-tools).
3. Now, enable USB Debugging on your device.
4. Turn off your Nexus and boot it into bootloader mode by pressing Power and Volume Down buttons together.
5. Connect your Nexus to your computer with a USB cable. Go to the ADB Tools folder, open a command window there (press Shift key, right click and select ”Open command window here”) and issue the command fastboot oem unlock to unlock the bootloader.
6. Once unlocked the bootloader, go to the unzipped system image directory and double click the flash-all script. It will install the Android M on your device.
7. Once the installation finishes, your device will reboot into Android M.
Troubleshooting:
1. If your Nexus stuck in a bootloop, boot your device into Recovery mode (press and hold Volume Up + Volume Down + Power buttons) and wipe the cache partition and wipe data/factory reset.
2. If you get an error message saying missing the system.img file while flashing the OS, then do the following.
Unzip the image.zip, copy and paste the content into the unzipped system image directory (ADB Tools folder). Then open a command window there and issue the following commands:
fastboot flash bootloader < bootloader-filename >.img
fastboot flash radio < radio-fileame >.img
fastboot reboot-bootloader
fastboot flash recovery recovery.img
fastboot flash boot boot.img
fastboot flash system system.img
fastboot flash cache cache.img
fastboot flash userdata userdata.img
Once the process is completed, your Nexus will reboot into Android M. Enjoy! (Source)
