(This is an updated version of a thread I originally posted on GBAtemp in March 2021.)

The current method for dumping a Wii U kiosk system (CAT-I, CAT-SES) requires using a hardmod to dump the eMMC, then using Recovery Mode to install SDK 2.13.01 and dumping the keys. It turns out that, if the kiosk system has a recent enough firmware, it’s possible to dump the eMMC (and SLC, etc) without any hardware modifications.

The Wii U operating system (IOSU) includes a debug logging facility (enabled on devkits only) that logs debug output to two places:

• Ethernet (CAT-DEV only)
• USB Serial (CAT-DEV, CAT-R Reader, CAT-I Kiosk, CAT-SES Kiosk)

In addition to simply logging debug information, the serial console can be used to run a limited set of commands in the cos shell, as long as the system is in Development (not Production) mode. It turns out that, on recent enough firmware versions, there’s a cos shell command to launch a title, and this can be used to launch System Config Tool.

Devkit models, in case you’re unfamiliar with them:

A description of the above systems, from left to right:

• CAT-I: Disc-based kiosk system. Usually has a white Wii U chassis.
• CAT-DEV: High-end debugging system in a metal case. This system has PC connectivity over Ethernet. (Also shown is a DRC-DK-MP development gamepad.)
• CAT-R Reader: Standard test system, with limited debugging capabilities. Looks like a white Wii U with a green faceplate.
• CAT-SES: HDD-based kiosk system. Usually has a black Wii U chassis. The two front USB ports are used by the internal HDD.

This guide is generally not needed for CAT-DEV or CAT-R units, but it should work with them regardless.

Preparations

You will need the following:

• Wii U development console (CAT-DEV, CAT-R, CAT-I, CAT-SES)
• SD card (64 GB or larger, formatted as FAT32)
• USB serial cable with FTDI FT232 chipset
• Debug-signed version of Homebrew Launcher for Wii U
• Wii U NAND Dumper
• TeraTerm Pro, or similar serial terminal program

Serial cables known to work with Wii U’s debug logging:

• If you do not have a serial port on your PC:
  • FTDI USB-NMC-2.5M: https://www.digikey.com/en/products/detail/ftdi,-future-technology-devices-international-ltd/USB%2520NMC-2.5M/2441364
• If you do have a serial port on your PC:
  • Digitus DA-70156 USB to Serial adapter: https://www.amazon.com/gp/product/B0030IT780
  • StarTech.com 10′ null modem serial cable: https://www.amazon.com/StarTech-com-10-Feet-RS232-Serial-SCNM9FF/dp/B00006B8BJ
  • The important part here is the USB adapter, which connects to the Wii U, must have an FT232 chipset, since that’s the only chip supported by IOSU for debug logging.

Instructions

Serial Cable Setup

1. Connect the USB serial cable to the Wii U and to the PC.
   If using the USB-NMC-2.5M, connect one end to Wii U and one to PC.
   If using a USB Serial adapter, connect the USB side to the Wii U, the null modem cable to the USB Serial adapter, and the other end of the null modem cable to the PC.
2. On the PC, open TeraTerm. Select Serial and select the COM port that corresponds to the serial cable, then click OK.
3. In TeraTerm, click the Setup menu, then Terminal. Set New-line for both Receive and Transmit to CR+LF, then click OK.
4. In TeraTerm, click the Setup menu, then Serial port. Select the COM port that corresponds to the serial cable, set the speed to 57600, then click the “New setting” button.
5. Turn on the Wii U. In 5-10 seconds, you should start seeing debug messages printed on the console.

cos shell

To determine if the cos shell is working, type the following in the serial terminal, then press Enter:

cos sdkversion

If cos shell is working, and the system is set to Development mode, a message similar to the following will be printed:

cos sdkversion
# 00;01;55;243:
---- COS Debugging Shell Command: sdkversion ----
00;01;55;243: SDKVer:21301

In this example, the system has SDK version 2.13.01 installed. This is the latest version of the system software, which corresponds to Wii U menu 5.5.0.

WARNING: If anything other than 21301 is displayed, you must stop here for now. Both the dev-signed Homebrew Launcher and Wii U NAND Dumper only function properly with the latest version of IOSU, indicated as SDK 2.13.01. However, if the system is new enough, e.g. 2.12.12 or 2.12.13, it’s possible to update just the IOSU title to the latest version, but this requires a copy of the development version of IOSU. This is named os_v10_ndebug and may be found in the latest SDK and in newer CAT-I kiosk disc images. If you do in fact have 2.12.12 or 2.12.13 and a copy of os_v10_ndebug, you can continue to the next section.

Launch System Config Tool

To launch System Config Tool, run the following command in TeraTerm:

cos launch 0x00050010 0x1F700500

This will result in one of the following:

1. Nothing (just a ‘#’): The SDK version may be too old, in which case it doesn’t have a launch command. Unfortunately there’s no known workaround for this at the moment, other than dumping eMMC manually. (CAT-SES units may have SDK 2.09.xx, which doesn’t have the launch command.)
2. Errcode -6: The specified title ID was not found. Make sure you entered it correctly. Note that some older firmware versions might have a different menu called DEVMENU installed, and DEVMENU has a different title ID.
3. System Config Tool will load. This is what we want!

If either #1 or #2 happens, you’ll need to stop here for now. You can post in the GBAtemp thread for support questions.

System Config Tool

Set the default title to System Config Tool:

1. Select Boot Configuration.
   
   
   
2. Select Default Title.
   
   
   On this system, we have four Menus available: Kiosk Menu, DEVMENU (listed as “Short Title Name (EN)”), Wii U Menu (USA), and System Config Tool.
   
3. In the Default Title menu, select System Config Tool, press A to view title information, then press A to select.
   
   
   
   
4. Power-cycle the system. It should boot to System Config Tool instead of the Kiosk Menu.

Install Homebrew Launcher:

1. On PC, extract the debug-signed version of Homebrew Launcher to the SD card.
2. Also extract Wii U NAND Dumper to the SD card. This will be used later.
3. Put the SD card in the Wii U.
4. In System Config Tool, select Data Manager, Title Manager, Install.
   
   
   
   
5. Select SD Card, then browse to where Homebrew Launcher was copied.
   
   
   
6. Homebrew Launcher will be detected as an Install Image. Highlight it and press A to select the title for installation.
7. Press R to install. Follow the prompts to continue installation.
   
   
   

If your system has SDK 2.12.12 and you have a copy of os_v10_ndebug from SDK 2.13.01:

1. On PC, copy os_v10_ndebug to the SD card.
2. Put the SD card in the Wii U.
3. In System Config Tool, select Software Version Information to verify the installed SDK version.
   
   
   Here we can verify that the OS SDK version is 2.12.12. The OS title ID is below. Note that it seems to indicate we’re using the DEBUG version (800A), but it’s actually using the NDEBUG version (400A).
   
4. In System Config Tool, select Data Manager, Title Manager, Install.
   
   
   
   
5. Select SD card, then browse to where os_v10_ndebug was copied.
   
   
   
6. os_v10_ndebug will be detected as an Install Image. Highlight it and press A to select the title for installation.
7. Press R to install. Follow the prompts to continue installation.
   
   
   
8. Power-cycle the system.
9. Verify that os_v10_ndebug was updated by select Software Version Information and checking the SDK version. Here, we can see that the SDK version was updated to 2.13.01. (The System Config Tool version isn’t relevant here, since that applies to System Config Tool itself, not the OS.)
   

Wii U NAND Dumper

WARNING: This step requires changing the system mode to Production. After this setting is changed, DO NOT RUN ANY KIOSK TITLES. Doing so may result in Kiosk Menu being set as the default title, and cos shell will not accept any commands while in Production Mode. If this happens, and you have SDK 2.13.01 installed, you can use udpih to reset the startup title to System Config Tool.

Set the system to Production Mode:

1. In the System Config Tool main menu, select Boot Configuration.
   
   
2. Set System Mode to Production Mode and save changes.
   
   
   
3. Power-cycle the system. System Config Tool should load.

Run the Wii U NAND Dumper:

1. In System Config Tool, select Title Launcher.
   
   
2. Select Homebrew Launcher, press A to view details, then press A twice to load it.
   
   
   
   
3. In Homebrew Launcher, load Wii U NAND Dumper.
   
   
   
4. In Wii U NAND Dumper, enable dumping of everything, including slc, slccmpt, mlc, otp, and seeprom.
   
   The default settings dump everything except MLC, so make sure you enable MLC dumping:
   
   
5. Dump everything. The system will look like it’s rebooting, but a progress indicator will be printed on the gamepad screen. If it crashes instead of showing progress, make sure you set the system to Production Mode and try again.

Switch Back to Development Mode

After dumping the system’s NAND, put the system back in Development Mode to re-enable commands on the serial port:

1. In the System Config Tool main menu, select Boot Configuration.
   
   
2. Set System Mode to Development Mode and save changes.
   
   
3. Power-cycle the system. System Config Tool should load.

Final Steps

Save the NAND dumps in a safe place for later use. You can use wfs-tools to extract files from the MLC dump and NUSPacker to build installable packages. (Note that NUSPacker doesn’t use the original ticket, and may need some adjustments to work properly with dev-signed packages, so it won’t be 100% identical to the original kiosk packages, but it’ll be close enough.)

As an optional step, you can flash SDK 2.13.01 and Wii U Menu Changer. This will wipe the system and effectively turn it into a standard devkit. This requires DDI recovery image files from the official SDK that cannot be linked here and are beyond the scope of this guide.

If you don’t want to wipe the system, you can keep System Config Tool as the startup title, or switch to Wii U Menu. Note that Wii U Menu might not load due to Kiosk Menu making some adjustments to the accounts, so you will need to set the “Launch State” option in Boot Configuration to Stage 0. This will tell Wii U Menu to initialize user accounts. Do note that launching Kiosk Menu will erase the user accounts again, so switching back to Wii U Menu may require setting “Launch State” back to Stage 0 again.