In this test case, using the "Sega Rally Revo" DATA.BFS file.

MD5: eb3a74cc08a9b16efe7d84183da09b06

Steps:

1. Extract the files from "DATA.BFS" using "extract" subcommand to a folder.
2. Recreate "DATA.BFS" using subcommand "archive" pointing to the folder in question:

bfstool.exe archive --format v2 --filter srr data.bfs data

The newly created DATA.BFS will have a smaller filesize, in this specific case, 125 MB (131,173,513 bytes) compared to the 130 MB (136,341,174 bytes) from the original.

Using UMDGen, insert newly created file into Sega Rally Revo ISO file, replacing the original one.
Optionally, LBA can be adjusted, but the game in question does not have LBA protection.

Upon testing the new ISO file, in emulator or hardware, the game won't boot.