Root + new ROM on Xiaomi Redmi 2 (2GB RAM version).

Got a Redmi 2   2GB RAM.

1. Root phone

Really simple.
http://xiaomiadvices.com/root-xiaomi-redmi-2prime-on-miui7/



2. Install a recovery manager

First, identify the exact model. The number is in the area occupied by the battery and in the box. Mine is 2014811

Now, install a proper recovery manager, because the one that comes with the phone is pretty useless.
https://thebroodle.com/xiaomi/redmi-2/how-to-install-twrp-recovery-in-xiaomi-redmi-2-tutorial/

You can install Flashify without going through Play Store. Just search for Flashify apk and select the one with the latest version.



3. Install a new ROM

From Flashify, go into "Reboot in recovery mode" and then once you are in recovery install the ROM you want.
I used this one.
http://www.htcmania.com/showthread.php?t=1031073

Update: the version 20/08/2015 gave me lots of problems and I installed an earlier one (CM11s_REDMI2.zip  394MB) that was always great on this Xiaomi Redmi 2 (2GB).