In each 2236 bytes sized sector dump (from the cache), the ecma 267/337 asserts that bytes 2061 to 2064 are error check bytes on the previous 2060 bytes (without any scrambling from the linear feedback shift register).
So I ran the 2060 bytes after the scrambling was removed, through a subroutine from friidump which does this error check calculation, to see whether it replicates these 2061->2064 error check bytes. It turns out for the first few hundred sectors, these calculations were a respective match with their corresponding 2061->2064 error check bytes.
Reading further through the friidump source code, it appears for nintendo wii discs the schedule of initial seeds for the scrambling algorithm are not officially known. So friidump attempts to guess the seed schedule, where they do an error check calculation on each guess to see whether it matches with the 2061->2064 error check bytes. Initially when friidump is first invoked, it performs this “seed guessing”.
More generally, I haven’t been able to figure out what exactly is the purpose of this scrambling (with the linear feedback shit register). For example in the case of generic dvd, it doesn’t appear to have any obvious cryptographic purposes.