Nexus 7 2013 error upgrading from 5.0.1 to 5.0.2 The 5.0.2 update fails.  This Nexus 7 (2013) has not been rooted or anything special like that.  I double tap to install update, it reboots, starts the install, then just says "error" in red over the android.  It sits there for 30 seconds or so then reboots into the previous OS, 5.0.1., which still works fine.  In a day or so it want to try again and still fails with error.  Any ideas?
So I have had this problem and saw it was not fixed. If you follow the official guide here: https://developers.google.com/android/nexus/images#razor you can manually flash and upgrade. That will reset your tablet so you may want to not do this.

To flash a system image:


Download the appropriate system image for your device from the internet (You can use the link above to find one), then unzip it to a safe directory.
Connect your device to your computer over USB.
Start the device in fastboot mode with one of the following methods:


Using the adb tool: With the device powered on, execute: adb reboot bootloader
Using a key combo: Turn the device off, then turn it on and immediately hold down the relevant key combination for your device. For example, to put a Nexus 5 ("hammerhead") into fastboot mode, press and hold Volume Up + Volume Down + Power as the device begins booting up. 

If necessary, unlock the device's bootloader by running: fastboot flashing unlock or, for older devices, running: fastboot oem unlock.
The target device will show you a confirmation screen. (This erases all data on the target device.)
Open a terminal and navigate to the unzipped system image directory. 
Execute the flash-all script. This script installs the necessary bootloader, baseband firmware(s), and operating system. 


Once the script finishes, your device reboots. You should now lock the bootloader for security:


Start the device in fastboot mode again, as described above.
Execute: fastboot flashing lock or, for older devices, running: fastboot oem lock


Locking bootloader will wipe the data on some devices. After locking the bootloader, if you want to flash the device again, you must run fastboot oem unlock again, which will wipe the data.