Modify Wii sd.raw files on Linux?

[Roadhog360]

Title. WinImage seems to run poorly with Wine and is just a trial that I need to eventually pay for anyways, I am hoping to find a permanent solution which works on Linux and isn't a trial for a program I need to pay for. "sd.raw" is too broad to look up on Google and I can't find any results on Google which are what I am looking for even if I try to explain what I am looking for.