Moments after the OTA .zip for the Nexus 9 Android 5.1.1 update was captured, Google went ahead and posted up the factory image for it as well. So for those of you who don’t want to “adb sideload” the over-the-air file, you can now flash an entire factory image.
Here are the instructions on how to flash a Nexus factory image.
Go get it.
Factory Image Link (Nexus 9 WiFi)