[Masquerade]

Thank you for the explanation.

I'm following slightly, here's what I understand:

Data1.bdh contains the sound folder, so you can use sfk to remove it (effectively removing the duplicated data) then after installing you can patch the sound folder back in by using sfk again.

In order to remove the data from the blocks above you need hex editor or convert them in decimal and use sfk, then zero them out and patch them back into position as shown in re3.

So from this I gather that in the hex editor, it will show address "17f332aa" and then you go to address "1b898ca9" and replace all of the data between these 2 addresses with 0s so that it essentially becomes empty - leading to a deduplicated file with more efficient compression - yes?

its only 7 blocks so use hex editor it will fast

Are all of these blocks in Data1.bdh or are they scattered over the 5 data files?

Using a xdelta or zstd patch or bsdiff is a bad idea since you know what blocks to remove/inject.

So If you didn't know what parts of a file to remove and reinject, how would xdelta help? I thought xdelta can only create a patch based on an old file and a new file (by creating a patch with changed data betweeen the 2) - this part confuses me, because how will you be able to know which part of the file to remove?

I see the method would be create an xdelta patch using the modified, smaller file, and the original file then apply it after installing.