One of Google’s selling points on KitKat was that it could run on low-power devices and phones with as low as 512 MB of RAM, but no one realistically expected extremely old devices to get official KitKat support. Of course, that’s never stopped Android’s developer community, and as of today both the Nexus One and Nexus S (yeah, remember those?) have unofficial KitKat ROMs. Best of all? They actually run pretty well.
The Nexus S ROM is still in alpha, but most major things are working. It has some issues with graphics drivers and some Google apps not working, but otherwise, most other tasks work extremely well. The Nexus One KitKat isn’t quite as stable, as it has several camera issues, no support for video recording, and you’ll need a custom bootloader to even use it. That’s definitely not something most people would want to bother with, but if you can get over those initial hurdles, it runs well enough for a device as old as the Nexus One.
Time to shake the dust off your old Nexus devices and flash away!