I have no idea about programing or anything like that, but see this:
https://www.mobileread.com/forums/showthread.php?t=83201
I tried the Chinese firmware on my K2US and it works. I didn't like it too much, so deleted it again. But it can co-exist with the normal Kindle system and you can switch between them. It seems to me that it is somehow invoked before the normal Kindle system loads.