I know this is the Wii section, but an attempt was also made for a XBOX ISO scrubber/unscrubber with partial success. Unfortunately, it seems there are 2 type of "seeds": the 1st one can be bruteforced and works for a few hundred ISOs, but the 2nd one seems to be impossible to calculate. Maybe someone with a fresh pair of eyes and technical knowledge could take a look at the topic in the redump forum (search for "Xbox shrinking tool needed") and the linked reddit page where help was asked for the 2nd seed type. The code for the tool was open sourced, if it helps.