Android Developers Blog: Strictly Enforced Verified Boot with Error Correction | Android Developers Blog
In other words:
Via scmagazine
"Android uses multiple layers of protection to keep users safe. One of these layers is verified boot, which improves security by using cryptographic integrity checking to detect changes to the operating system. Android has alerted about system integrity since Marshmallow, but starting with devices first shipping with Android 7.0, we require verified boot to be strictly enforcing. This means that a device with a corrupt boot image or verified partition will not boot or will boot in a limited capacity with user consent. Such strict checking, though, means that non-malicious data corruption, which previously would be less visible, could now start affecting process functionality more."
In other words:
"A system integrity feature that prohibits Android mobile devices from booting when the presence of malware is suspected will now be strictly enforced in version 7.0 (Nougat). Unfortunately, the function is so sensitive, it also prevents perfectly legitimate boot attempts when a harmless, non-malicious data corruption surfaces during the start-up process."
Via scmagazine