I didn’t know something like this existed.
What I made was a project that uses linkalho and two swtich units to re-sign save data.
Thanks for letting me know.
I’ve managed to bypass the checksum.
I’ll take a look at it now.
I've developed a script that can modify the Save Data UID for creating "Self-Brothers." Would anyone here be interested in me sharing it, or is there already an established tool for this?