: By-passing Microsoft's security to flash non-original firmware. Enable Mass Storage Mode
The bootloader is locked by default to prevent non-Windows operating systems from running. Nokia Lumia 520 - Transfer media to & from computer - AT&T nokia lumia 520 custom rom work
Unofficial upgrade using registry hacks to make the phone identify as a Lumia 950. WUT (Windows Universal Tool) nokia lumia 520 custom rom work
The cornerstone of any custom ROM work on the Lumia 520 is the Windows Phone Internals (WPI) nokia lumia 520 custom rom work