WarningPlease note that all data on the device will be lost. I do not take any responsibility whatsoever in the unlikely event that your device gets bricked. By following these instructions, you agree to take full responsibility of the consequences.
Step 1: Initial Setup
On your Mac, head into System Preferences and select Keyboard > Shortcuts > Services. Find the “New Terminal at Folder” in Services > Files and Folders and check the box. This enables us to launch Terminal in a specific folder.
Step 2: Download FilesDownload the Nexus 7 System Image. File size should be around 502 MB.
Next, Download the ADB & Fastboot Files as well, which is a minuscule 575 KB.
Step 3: Terminal Setup
Connect your Nexus 7 via USB and extract the ADB & Fastboot Files archive, and navigate to the folder – in my case fastboot.
Extract files in the Nexus 7 System Image archive and place it in our fastboot folder. Open “flash-all.sh” in a text editor and add “./” before the term “fastboot” on lines 17, 18 and 20. This will ensure that Terminal executes files in the same folder.
Go one level up in the folder heirarchy, right-click on the fastboot folder and select “New Terminal at Folder”. This will launch Terminal for that folder.
Step 4: Installation
Start the device in fastboot mode: press and hold Volume Down + Power as the device begins booting up. Make sure your bootloader is unlocked. If not, type the below.
./fastboot oem unlock
Finally, type the below and you will see a percentage progress of your files being sent to your tablet. Now sit and wait while Marshmallow is being installed. The entire process will take anywhere from 5-10 minutes.
Your device will automatically reboot and you will be done.
ImportantPlease note that the first boot can easily take over 7 minutes.
That’s it. You are done! Do share your feedback/experience in the comment section below.