Development for the Lumia 520 (codename: fame ) has seen several major ports over the years:
Stripping away bloatware to maximize the 1.0 GHz dual-core Snapdragon S4 processor. Nokia Lumia 520 Custom Rom
One of the most stable Android ports for this device. It allows for basic multitasking and access to older versions of modern apps. Development for the Lumia 520 (codename: fame )
Though never officially released for the 520, enthusiasts can use "interop unlock" hacks to trick the device into installing Windows 10 Mobile builds, allowing for better synchronization with modern Microsoft services. Prerequisites for Flashing Nokia Lumia 520 Custom Rom