Xiaomi Redmi 2/Prime are in Lollypop yet. Xiaomi has released MIUI 8 China Developer ROM for Redmi 2/Prime.
MIUI 8 Global release will take time. It’s better to install China Developer ROM and test MIUI 8.
- TWRP installed. Click here to see how to install twrp
- At least 60% charge
1. Download the ROM from above link and put it into the external memory
2. Boot your device into recovery. Press volume up and power button at the same time.
3. Take a backup in case your device is bricked and wipe data
4. Click on Install button and navigate to ROM file. Now select it and confirm the flash.
It’ll take 5-10 minute. Be patience and wait. After installing your first boot can take up to 10 minutes. Don’t panic.
All above steps are nicely described in the below video. Here is the video showing MIUI 8 overview and installation guide on Redmi 2/Prime.