Android Lollipop 5.1.1 was recently released for the Nexus 5 as a maintenance update to the latest OTA update of 5.1.0 to fix numerous issues, such as an intermittent non-response camera and excessive memory usage leading to crashing applications.

If you have a rooted phone or a phone with a custom recovery, you may find that the OTA update doesn’t work on your phone – this is because the update process now checksums and verifies partitions such as recovery before performing the update. If the partitions don’t match the expected stock ROM, the update process will terminate. Having a rooted phone (with the su binaries), modified radio, modified recovery, or custom ROM may all contribute to an update failing and bombing out.