Chosen Solution
My phone restarts every 5-10 seconds. I had this issue before and back then pressing the power button multiple times until the phone had fully booted fixed it. However, this now only helps to prolong the time until it reboots for a few seconds, but isn’t a fix anymore. Is it a power button issue or a software issue? (The problem started (like the time before) right after the last software update)
Here are some troubleshooting tips You can put your nexus in safe mode :) Nexus 5 Troubleshooting
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.[1] 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. [1] 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.
