Google makes restoring Google Nexus devices to original factory firmware easy. Google provides factory images for all Nexus devices because most developers will install custom ROM based on Android Open-Source Project. And this factory image will make Nexus device return to its factory state. Same apply to Google Nexus 7. We can download Nexus 7 factory image and flash it.
You can download Google Nexus 7 factory image directly from Google Developers website (link). Or use Google Nexus 7 ToolKit to download it for you.
