And of course, the file is just an executable that decompresses a firmware. No reason to require a windows or a mac to process this! But it's a massive pain to deal with this on Linux...
So to make your life easy: Here's the file! It's a .fir file, downloadable directly and uncompressed from my website. It doesn't cost anything, it's free to use and download from Canon, except now you don't have to deal with their crap windows/mac requirement which has nothing to do with your camera!