Google has bragged about its Pixel 3 phones' custom Titan M security chip, but... what is it doing, exactly? The company is happy to explain. It posted a summary explaining the core of what Titan M does, and it's clear the part is at once a watchdog and a safekeeping box. The chip is tied into Android's secure boot process and saves the last known-safe Android version to prevent attackers from rolling you back to an insecure firmware version. It also blocks attempts to unlock the bootloader (and thus run whatever firmware they like) from within Android, and they can't update your firmware unless you've entered your passcode.