Just sharing what i found
"First of all I downloaded the game using uTikDownloadHelper.exe
download Mario Party Japanese and European
Then I extracted the files using CDecrypt
of the 2 games
(I used this command "CDecrypt title.tmd title.tik"
I left the executable (CDecrypt) in the same folder as the game files)
After that I looked through the folders where the language files were
So what I did was as follows, I copied the files from the Portuguese folder (D: \ wiuu \ Mario Party 10 (EUR) \ content \ mess \ EU_Portuguese) of the European game and replaced them with files from the Japan folder (D: \ wiuu \ Mario Party 10 (JPN) \ content \ mess \ JP_Japanese) in the Japanese game
(I realized that if I delete the Japan folder and put the Portuguese folder in its place, the game freezes, I imagine and the Japanese version should have more files and would be missing, so I copied and put the game files in Portuguese)
I did a test on the Cemu emulator (because it takes a long time to assemble and install on wiiu)
Everything was fine at Cemu, so I did the following
I downloaded NUSPacker.jar and put it in the folder (D: \ wiuu)
Then, I created a folder like this (D: \ wiuu \ Mario Party 10 (JPN) _descompress) here I put the modified version (the one I tested at CEMU)
this folder should only contain (code, content, meta)
in the folder (D: \ wiuu) I created a file with this name "encryptKeyWith" exactly like that without a file extension
I edited this file with a text editor and put the "Wii U Common Key" (I don't think I can post the key here, on google, you find it easy)
only the key, in the first line of the file
soon after I created another file with the name "repacked.bat" in the folder (D: \ wiuu )
I put this code in this file
java -jar NUSPacker.jar -in "Mario Party 10 (JPN) _descompress" -out "Mario Party 10 (JPN) -repacked"
after it was finished, I installed it on my Wiiu with WUP
I suggest testing with the mario party to make sure you understand"
i copy from github spiik discussion credit to @machadoguilhermebr
I tried his way, it works.
And i found another way easier,
Open ftpiiu everywhere, connect to ur pc, browse the usb in ur WiiU
Example for game mario 3d world
you need install eng version and jap version
Copy from
... \ mario eng \ content \ LocalizedData \ UsEn
Replace To
... \ mario jap \ content \ LocalizedData \ JpJa
Then you can run jap version with english in jap console.
(u can delete the eng version already)
No need to run spiik
Hope it helps.