From Android 7 or "Nougat" Google incorporated a security feature in the system that verifies the integrity of the computer software during startup. It is not only in charge of checking if the system is safe or corrupt, but also allows action on the matter. Instead of simply warning when a serious problem is generated or exists on the computer (something that Android 6 was already doing ), Android Nougat allows the user to choose what to do. You can prevent the device from booting if the device believes there is a threat to your data, or you can choose to start the computer in "limited functionality" mode. This is what Google calls " Strictly Enforced Verified Boot "(" Strictly enforce a verified boot ") and yes, it basically checks that the Android system is official and not tampered with..
Xiaomi MI 5 boot screen
Virus warning and limited functionality in case of "bootloop"
A virus or malicious software may have been installed in the operating system. In that case, it is likely that the user does not want to continue using the equipment and does not compromise their information. The option in this case will be to solve the problem to use the device again.
If it is simply an error or failure of the device, it is likely that the user wants to continue operating the equipment, isolating the functionality affected by said failure. This is apparently possible since Android 7. It was not so with previous versions of Android. If, for example, some corrupted data in the operating system generated a "bootloop" problem or constant restart, the cell phone was useless if that software problem was not solved..
Apparently, this feature included since Android 7 only applies to devices with a blocked bootloader. Those with the bootloader unlocked probably have no additional trouble installing unofficial Android software, rooting, or modifying the system. On these mobiles, this additional "Strictly Enforced Verified Boot" security check would simply not be performed.
This may not always be this ideal . Google indicated that the impact of this feature could harm the user experience. This functionality will become apparent every time there is a hardware or software failure in the computer. It does not matter if the failure is so serious that the cell phone cannot start normally or it is slight errors in the Android system..
More information : developer.android.com , via : Engadget
Top 13 Android 7 Features: Multi-Window, SD Save, Doze, and More
Bootloader locked, a nightmare on Xiaomi devices
Motorola stays on the logo and restarts constantly (Moto G case)
