Alternate OSes for old Kyocera Echo?

[CommanderLiamTHX]

Hello all, I had this terrible phone known as the Kyocera Echo in 2011. I have since then upgraded, but I came across the little beast a couple days ago. I was wondering if I could uninstall Android and wreck it with something else, and I was wondering where to start with that. I've been thinking of Firefox OS, but that requires at least 4.0 or higher, and the Echo went up to 2.3. I also found a tutorial on Windows CE, but I wasn't sure if that would work well or not. Any ideas?

P.S. The WinCE tutorial is here: https://www.youtube.com/watch?v=bIS8ehAUg44