原帖由： David Spalding ,
I've had the endless boot animation problem before, it's hard to tell if an application's data is causing the issue, or an app itself. I don't believe there's a way to boot into Safe Mode from bootloader. I'm afraid your arguably easiest fix is to factory reset it and configure it again. Sometimes when a Nexus is stuck in bootloop, I'll hold the POWER button down until the screen goes blank again, and without releasing the POWER button, hold VOL DOWN. That may get you into bootloader. From there enter Recovery, and in Recovery you can factory reset it. It should boot normally and then take you through setup.  Google's information for the Nexus 5 states that bootloader is reached with both VOL UP and VOL DOWN along with POWER, but my refurbished unit works with only VOL DOWN and POWER.