Volume key unkown for an ISO file. The original disc opens fine.

[babypuncher]

I bought a copy of Onward from Amazon, but it came with a circular scratch from the factory that prevented me from ripping it with MakeMKV.

Amazon sent me a replacement disc, which also has a scratch, but in a different location.

I made a complete rip of this disc using ddrescue to fill in the missing bits from one disc using the other.

When trying to open the resulting iso file, MakeMKV complains that the volume key is unkown, even though it had no trouble finding the key when reading either disc directly from my blu-ray drive.

Is there any way to fix this?

[SamuriHL]

Nope. You can't just make ISO images like that. They're bus encrypted and can never be decrypted.