rename some files

tools/Filesystem/README.txt

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+╔═════════════════════╗
+ SEGA Decryption Guide
+╚═════════════════════╝
+
+╭─────────╮
+ app files
+╰─────────╯
+
+1. create a new file titled <PCB CODE>.bin
+
+2. fill in the first 16 bytes of <PCB CODE>.bin with
+the AES key. (e.g. 9D 0B BA 20 D1 E8 4F 24 59 39 9F 53 83 BE EE 72)
+
+3. the next 16 bytes will be the NTFS header (EB 52 90 4E 54 46 53 20 20 20 20 00 10 01 00 00)
+the NTFS header is always the same
+
+4. save this file, then decrypt the app files with the following command:
+fsdecrypt <PCB CODE>.bin 0x200000 <path/to/app> <out.vhd>
+
+5. once it finishes decrypting, run the calculate_iv.py script
+save the output of key 1. script is found here: https://discord.com/channels/162861213309599744/243895668790394882/995170669329391706
+
+6. open <PCB CODE>.bin inside the hex editor once more, replace the NTFS header with
+the key 1
+
+7. run "fsdecrypt <PCB CODE>.bin 0x200000 <path/to/app> <out.vhd>" once more
+
+8. your app is now decrypted, you can extract the internal_0 with poweriso or any other tool
+
+╭─────────╮
+ opt files
+╰─────────╯
+
+1. decrypt the opt file using fstools with the following command:
+fstool dec OPT.bin in.opt out.vhd
+
+2. run the calculate_iv.py script and save key 3
+script is found here: https://discord.com/channels/162861213309599744/243895668790394882/995170669329391706
+
+3. replace the IV key of the OPT.bin with key 3, the IV key of OPT.bin are the second 16 bytes
+
+4. decrypt the opt file once more with the new key