Jellybean was Android 4.3. I think Android phones weren’t really usable before that. But I didn’t get one til much later. The Galaxy S3 originally came with 4.0 and later with 4.3. https://en.wikipedia.org/wiki/Samsung_Galaxy_S_III

No idea about your custom firmware ofc.

I have an old Android 2.1 music player (Archos 43) still kicking around. It’s slow and the Android software is not very good.