XTool 2020 (Plugins)

[KaktoR]

I will quote masquerade, maybe he will tell you how to process this.

A game came out called The Legend of Heroes Trails through Daybreak. They used ZSTD compression on the archives yet because they used dictionary based zstd, xtool can't detect the streams let alone process them.

[Masquerade]

^^
These p3a archives are made with dictionary ZSTD just like Zelda Tears of the Kingdom files.

You can rebuild the archives using p3a_tool and decide for no compression. If you decide on the zstd compression with p3a_tool, you still need to brute force a stream to figure out what version and settings for ZSTD were used.

I think there is more than one dictionary, they can be dumped from memory at runtime but that's about as far as I have got.

[Masquerade]

I cannot believe I was unbelievably stupid to not check the archives themselves for the dictionary. After looking more closely at the syntax for the p3a_tool, there is the option "info". So:

CMD> p3a_tool.exe info scene.p3a

PH3 archive scene.p3a: 916 files, v1200
Extended header available: 16 bytes, 304 bytes per index entry
compression stats: none:0 lz4:0 zStd:0 zStdDict:916
  compressed size:   89239105 (15%)
uncompressed size:  578417191
Has dictionary, 112640 bytes

From this info, we learn that the dictionary used in the archive scene.p3a is 112640 bytes in size.
The ZSTD dictionary compression format tells us that the magic number for a ZSTD dictionary is 0xEC30A437 (little endian).

So, by searching for this magic number in HXD, sure enough we have our dictionary beginning at location 0x44000 for scene.p3a. Next, select a block and set the length to the dictionary length from earlier - 112640 bytes.

Copy the select bytes and dump them to a new file, I called it scene.zdict.

Now, if you unpack scene.p3a with:

CMD> p3a_tool extract scene.p3a

and then run:

CMD> p3a_tool archive scene.MSQ scene --comp=zstd --dictionary=scene.zdict --

We yield a CRC identical P3A archive:

    File: scene.MSQ
  CRC-32: 04492de2
     MD5: b2c8a40571e8673ed3682df82544281d
   SHA-1: 95d40b6e693641ef8c7692531370fecd0378290c
  BLAKE3: 79c13b93a662d4789949c228e116a52ac10a47d91562bd39023a61cabd09d0ca

    File: scene.p3a
  CRC-32: 04492de2
     MD5: b2c8a40571e8673ed3682df82544281d
   SHA-1: 95d40b6e693641ef8c7692531370fecd0378290c
  BLAKE3: 79c13b93a662d4789949c228e116a52ac10a47d91562bd39023a61cabd09d0ca

So there you go, that's how to repack this game.