I'm trying to make changes to the Android framework as a part of a project. As ambitious as it sounds, I want to flash a Nexus S with an Android 5 image. Can this be done, or is there a limit to the Android version supported by a device?
Strictly Speaking I do not think so.
If you look on the google images for android site (https://developers.google.com/android/nexus/images) the highest the Nexus S goes is up to 4.1.2. Also, according to wikipedia (http://en.wikipedia.org/wiki/Nexus_S) the highest modded version is 4.4.3 KitKat via the CyanogenMod. Hope this helps.