What are some alternatives?
When comparing CopperheadOS and OmniROM, you can also consider the following products
LineageOS - Operating system for smartphones and tablet computers, based on the Android
MIUI - Xiaomi MIUI Official Global Site. MIUI is a customized Android ROM developed by Xiaomi for smartphones and tablets. MIUI Forum offers ROM downloads for 251 devices including Mi 6, Mi MIX 2, Redmi Note 4 and others.
Replicant - Replicant is a distribution of Android that is 100% Free Software.
Android - Android is an open source mobile operating system initially released by Google in 2008 and has since become of the most widely used operating systems on any platform.
Resurrection Remix OS - Resurrection Remix ROM is ultimately full featured, stable and combined with the best features of...
CyanogenMod - CyanogenMod is a custom version of the Android operating system.