For a long time now, Google has made factory images available with each new system update for Nexus devices, but the problem was, you had to have an unlocked bootloader in order to flash them. Not anymore. Starting today, Google now offers full OTA images for all currently supported devices. These are not the incremental OTAs which sometimes take weeks to fully roll out. These are full OTA images that you can simply sideload with adb in recovery regardless of whether your bootloader is locked or not.
shamu LMY48I from LMY47Z (International, Sprint, U.S.