Nexus 7 2013 error upgrading to 5.0.2 OTA I updated to 5.0.1 via OTA sometime ago, and it worked fine. Now I got a notification that 5.0.2 is ready but when Android shuts down to install update it returns error (with no other message. My Nexus 7 is rooted but has the stock recovery.

Is there an easy fix that doesn't require factory reset or installing recovery?
Since Android 5.0, any modifications to /system will cause OTA updates to fail. Android Police noted that:


  ... the OTA script no longer patches individual files. Instead, it patches
  the system block directly and treats it as one enormous blob.


Therefore you have 2 choices if you want to update your device.


Remove any modifications to the system partition and remove any files that you may have added/renamed and restore any deleted files.
Flash the factory image. For the 5.0.2 update you can probably flash just the system image although this may not be the case for later updates. To do this you can use the instructions in my answer here (although it is for a different Nexus device the procedure is the same, the file names may differ though). To just flash the system image you can just perform steps 1 and 6.