Originally Posted by Paul View Post
You will need to flash Clockwork Recovery or TWRP to your phone using Fastboot. After that you can then install a custom rom. XDA Developers have a huge list.

Here's one for the phone that's Android 5.1.1

http://forum.xda-developers.com/show....php?t=2799765

When flashing a new ROM, you will lose EVERYTHING and have a good chance of bricking your phone. From one of the recoveries it's recommended that you do a full backup.
Why do I need to flash? And after flashing, I'll download 5.1 firmwares? And how do I do full backup? Can ES File Explorer will do? Sorry, never been tried it.

And is that u on xda?