The custom ROM team has also released an experimental Android 5.0-based CM 12 ROM for the smartphones and the nightlies will begin soon. As all of the available Android One smartphones – Micromax Canvas A1, Karbonn Sparkle V, Spice Dream Uno, and Symphony Roar A50 use the same hardware and software builds, there is a single CM build for all the devices and it can be found under “sprout” codename on the CM website.
The current experimental CM 12 build is not meant for everyone and if you want a software build that won’t create problems in daily-usage, you should wait until the first CM 12 M-release.
In addition to Android One phones, CM team has also added support for Nexus 6 and LG G3 D855.
CyanogenMod is the most popular after-market firmware for Android devices. It is based on AOSP Android and comes with several of its own customisations.