Question about Splash.z and Sound.z

[LightRayn]

Hello to whom ever is reading. I'm not sure if anyone has done this before, though I have found threads here and while searching google with people asking a similar question, though no real answers were reached. None that I've found anyway.

I was curious if I could change the Wii U splash screen (The one that comes up when you first start the system.) I don't remember exactly how but I stumbled across Splash.z and Sound.z using FtpiiU everywhere and WinSCP, in /storage_mlc/sys/title/0005001b/1005700/content/

I checked these files in a hex editor and there doesn't appear to be any notation of file type (Like the FST file has "FST" in the header.) I know typically a ".z" file type is a zlib compressed file, but no compression software has been successful decompressing either file. I've tried winrar, winzip and 7zip in windows, and zlib in linux.

Has anyone been able to decompress these files? I don't mind experimenting on this Wii U as I can just Defuse and restore the MLC backup.

Thank you for any help.

 

[LightRayn]

For who ever is reading, I've started picking apart the splash.z file and noticed the header seems a bit off. According to zlib documentation, the first byte called the "CMF" or Compression Method Flags should be "0x78". That doesn't appear until offset 0x04.
The sequence of bytes are as follows:
00 38 40 2C 78 9C
I'm not yet sure what the first 4 bytes are for. Possibly the initial size of the file compressed. 2C 40 38 = 2,900,024, which is about the same size as the bootTvTex.tga files used in other locations.
The reason I've included the "9C" is according to the aforementioned documentation, this byte proceeds the CMF and denotes the compression method, which in this case is the "default" compression method.
Upon further searching, I found that zlib archives that were compressed using gz_write have a header with 1F 8B 08 00 00 00 00 00 00 0B before the 78. I appended it to the beginning and moved the 00 38 40 to the end of the file and winrar opens it. Though it does complain about the Checksum being incorrect.
If anyone knows anything about this, or can correct me on anywhere I'm wrong, please do so. I'll continue playing around with it however.

 

[LightRayn]

Another little update. I used a program called "offzip" and it successfully extracted "00000004.tga" from splash.z. I'm going to use pigz in linux to recompress it, and compare the bytes. I figure I'll also modify the image a little to see if it shows on a wii u.
Funny how this turned into a status update thread more than a Q&A.

Post automatically merged: Apr 11, 2024

I've replaced the splash.z with a modified image and absolutely nothing has changed. I think I'm barking up the wrong tree. Guess I'll be looking elsewhere for the boot splash screen.

 

[LightRayn]

So I've changed the "Splash.z" image in the title 0005001B10057000, I've changed the splash bflm image found in /storage_mlc/sys/title/00050010/10040100/content/Common/Package/Men2.pack --> WiiUSplash.szs. I've changed icon images found throughout every title, not a single change is reflected on the console.

In case anyone is wondering, I use the MLC Restorer downloader to download the titles, decrypt & extract them with a python script I found linked on GBAtemp. Open the various pack, szs, zlib... files found within each extracted title with Switch Toolbox. Export the images, modify them, use Switch Toolbox to replace the images. Then with FTPii Everywhere and WinSCP I transfer the modified files to the respecting titles on the Wii U.

If anyone wants to try I can link to the tools. I'm ready to bang my head into the wall.