Factory images have just gone up for the Nexus 5 and Nexus 6, bearing the build name LMY47I. So what’s new here exactly? What we’re looking at is Android 5.1.0_r3, which appears to contain a few minor bug fixes. From Android Authority - Android 5.1.0_r3 factory images (LMY47I) arrive for Nexus 5 and Nexus 6