Here's the new update tool that I'm writing. It's written in pure C. My first "real" experience with C. Not anywhere near done. I'm just finished with extraction and haven't touched on creation. My goal is for it to be 1) lightweight (no need to download python), 2) fast (300MB update extracted in 5 seconds. took 5 minutes with the python tool), 3) portable (hopefully will work on osx, windows, linux, and arm-linux (on the kindle itself). I know the python tool is "good enough", but I constantly find problems with it, like slow extraction times on 300mb recovery updates. I also hope that some other experienced developers can help so I'm putting it on github.