Dumping files for Cemu's online mode

This guide assumes that you are already somewhat familiar with homebrew on Wii U. If not, a quick google search brings up dozens of guides. (Make sure that whatever guide you are following matches the firmware version of your Wii U)

What you need:
A way to run homebrew launcher
A SD card with NAND dumper (The capacity of the SD should be at least 64GB, or only 16GB if you have a Wii U model with 8GB internal storage)

How to dump system files:
1) Run homebrew launcher
2) Launch NAND dumper
3) Dump MLC to the SD card. Also dump otp and seeprom because you will need it for the later steps.
4) Merge the dumped MLC parts on Windows using cmd: copy /b mlc.bin.part01 + mlc.bin.part02 + mlc.bin.part03 + ...
5) Use wfs-extract (https://github.com/koolkdev/wfslib/releases) to extract files from the merged MLC dump
The command for extracting looks like this::
wfs-extract.exe --input.bin C:\wiiu_nand\mlc.bin --output C:\wiiu_nand\extracted\ --otp C:\wiiu_nand\otp.bin --seeprom C:\wiiu_nand\seeprom.bin

Alternatively, if you already have CBHX installed on your Wii U you can use FTPii everywhere to dump files (https://github.com/FIX94/ftpiiu/releases/tag/v0.4u2-cbhc)



These are the files that you need for Cemu:
1)
otp.bin and seeprom.bin (dumped via NAND dumper)
Put them in Cemu's root directory

2)
Certificates and keys:
storage_mlc\sys\title\0005001b\10054000\content\ccerts\WIIU_ACCOUNT_1_CERT.der
storage_mlc\sys\title\0005001b\10054000\content\ccerts\WIIU_ACCOUNT_1_RSA_KEY.aes
storage_mlc\sys\title\0005001b\10054000\content\scerts\CACERT_NINTENDO_CA_G3.der
Put into Cemu's mlc directory and keep the relative folder structure intact (mlc\sys\title\0005001b\...).

3)
Account data:
storage_mlc\usr\save\system\act\800000**\account.dat
If you have multiple accounts on your Wii U then every account should have it's own folder (80000001, 80000002, 80000003,...). You can open account.dat with a text editor to find the one that you want to use. Keep in mind that in order to work, the account must be linked with a NNID.

Copy the account.dat file to Cemu's mlc directory:
mlc\usr\save\system\act\80000001\account.dat (always copy to \80000001\.. even if the original account had a different number)

4)
Splatoon also requires SpotPass files to be dumped: /usr/boss/ (launch the game first on the console, then dump and copy to Cemu's /mlc/usr/boss. Must be repeated once a month)

Finally, you can activate online mode in Cemu 1.11.0 via:
Options -> Experimental -> Enable online mode
If you did everything right, it should show you a warning and ask for your confirmation. If something is missing, it will tell you what files exactly are missing.