This is a little painful (slow getting there) but, he imports CR2 files for file conversion within Siril..
Can't confirm it works as I haven't used Siril...
Be curious to hear whether this works for you...
https://www.youtube.com/watch?v=qYXd0rrAzjg
More info here:
https://free-astro.org/index.php/Siril:Tutorial_import