For several reasons, I still use a feature phone - specifically, the LG Cosmos 2.
Unfortunately, the interface is horrible. I mean, really horrible. If I receive a text message while in the middle of composing a text message, it interrupts me while I'm typing. It doesn't know how to properly receive group text messages, and it imposes a severe limit to the number of text messages I can store, despite the fact that I have an extra SD card installed.
Is there alternative, open-source software that I can install/flash onto my phone? I'd like to find a project analogous to Rockbox for MP3 players.