If you haven’t touched your RK3188 device since 2014, cleaning its heatsink, reapplying thermal paste, and flashing Wasser’s Android 5.1 will surprise you. It won’t turn it into a flagship, but it will make it fully usable for daily casual tasks – something the original Android 4.4 can no longer claim.
Rockchip RK3188 chipset, finding a "complete piece" of Android 5.1 Lollipop rk3188 android 5.1 firmware