I am creating this list here for all Error Codes related to NAND-AID/eMMC repair on the Wii U and how I fixed the error codes. This will make it easier than having to read through posts/threads in order to find them, both for me and for anyone else who may need this information.



Cause: Corrupted files/folders cause this Factory Reset Crash Loop when the system attempts to delete them and cannot. This will usually happen after writing a backup of the MLC to the SD and restoring the 52 titles with fresh downloaded ones. It doesn't repair the corruption that are in other locations.

There are a couple ways to fix this problem. Fix 1 gets you out of the crash loop and back into the Wii U Menu and may be the preferred method for those who wish to preserve save files or some other data. Keep in mind that this method also means you cannot do a factory reset without causing the same problem again. Fix 2 gives you a brand new/fresh file system, thus there is no corruption and the ability to do a factory reset is restored. This also means all data on the Wii U is deleted.

Fix 1: Use wupclient command delete_title() to remove all titles from /vol/storage_mlc01/usr/title/. If you need help installing/setting up an environment for that refer to this guide. Once you do that return to the recovery menu select "Set Initial Launch" and select option "0-Initial Setup". Restart the console and it should now boot. 

The better method in my opinion and my preferred method is to format the MLC and start with a brand new/clean file system with no corruption.
 
Fix 2: Download the fw file attached to this post. Then install ISFShax, using this guide. You will be using the UDPIH Method. Then you can Erase the MLC and rebuild the MLC, using this guide. I am not going to create guides for ISFShax or MLC Rebuilding because I believe the user SDIO has already done a perfect guide for both.

Note: since you are using the Erase MLC function you can ignore the "wafel_destroy" step in the MLC rebuilding guide above.

In order to Erase the MLC you have to be inside the minute menu and you want to select "backup and Restore" by scrolling to it using the power button and selecting it using the eject button.
Note: Minute menu swaps the buttons, power is now used to move the cursor and eject is used to select.


This will bring you into the Backup and Restore menu. Scroll down to "Erase MLC" and select it using the eject button.


Once you Erase the MLC. You should get a confirmation screen that looks like the picture below. If you got anything else something went wrong. Check to make sure you are using the fw attached to this post. Also verify you have setup your SD Card correctly with all directories/files as described in the ISFShax guide above.

If your screen looks like this, the MLC was successfully erased:


Return to the Backup and Restore menu, this time you want to scroll to "Delete scfm.img" 

This will delete the scfm.img. You need to do this after erasing the MLC. Hit the eject button to select this. It should only take a few seconds to complete.


Now you can begin to rebuild the MLC, by following this guide

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(confirmed)

Cause: The installation directory loses the correct permissions and updates for games can be downloaded but when they go to install (be written to memory) they fail because the directory where they install is missing permissions. Upon further investigation this only occurs after uninstalling ISFShax from the Wii U console. If you leave ISFShax installed the permissions for the directory are not lost and updates will download & install correctly. I have tested this across multiple Wii U and over a dozen times and I can repeat the error message only if I remove ISFShax after the initial setup of the console and then insert a game disc. Its worth noting that this doesn't always happen. It seems to only occurs on some Wii U consoles after a NAND-AID is installed.

Fix 1: This error has been resolved with version 2.0 wafel_setup_mlc, which can be downloaded here Use this to rebuild the MLC and the correct permissions remain when ISFShax is removed. I have tested and verified that version 2.0 no longer causes the problem. This is the best case scenario. I will leave the other fixes for those who used an older version of wafel_setup_mlc. If you used version 2.0 or later you shouldn't need to fix this with other methods.

Here is a video showing a mlc rebuild using wafel_setup_mlc version 2.0. This video shows a working folder permission after the removal of ISFShax. 

Fix 2: Don't uninstall ISFShax. Instead complete the "Booting without SD" section from the ISFShax Guide. Note: If you do a factory reset after following these instructions and you do not have an SD Card with the fw image on it. The Wii U will show a black screen with an orange LED. The fix for this is to put the SD Card back into the console with the fw image from this post. 

Fix 3: Setup homebrew on the console and check the permissions on the install directory using FTP. I believe the directory is /usr/packages. It would seem homebrew can be used to reset the permissions on the install directory. This is a lengthy process for a fix, but may be necessary if you have a console where you want to preserve data, rather than starting with a fresh console. 

Fix 4: Potential Fix: I installed an update for a game on the console. Then I restarted the console and removed the ISFShax. Then I installed an update for another game. This would indicate that permissions are correct. I am posting it because it may actually be a fix and its easier than installing homebrew if you just want to be able to remove ISFShax and have a working console. Further testing needs to be done to identity how reliable this method is. I have been able to repeat this on 3 consoles and it was successful. Albeit a small sample pool. 

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Cause: Currently unknown, Seen it on a single console that ended up dying. It is an error related to data corruption. This particular console would display it after downloading an update for a game. The strange thing is that some games downloaded/installed without a problem. The games that threw this error were Hyrule Warriors update download (957MB) and Wii Sports Club download. The Lost Reavers Notice downloaded and installed (157MB) without a hitch. Video of error is below


Fix:Defuse, use it to install ISFShax and rebuild the MLC.


Cause: It took 9 months for me to come across this again and this time I noticed what happen. This error is caused when the ground pad on the NAND-AID fails and it detaches from the Wii U board, thus causing the NAND-AID to malfunction. As a reminder the ground pad is required for the NAND-AID to work. The solder that are on some Wii U consoles is so poor that adding new solder to them doesn't create a strong enough solder joint. This can be seen under a microscope by applying slight pressure from under the NAND-AID. If the board flexes up the solder joint is weak and could break when soldering the SD Card Slot or inserting the SD Card. This error can also show up if any soldering point was missed or not connected and the SD Card cannot be accessed.


Fix: Solder the Ground Pad back into place. Unfortunately this will require removing the SD Card Slot from the NAND-AID unless you are using Version 4.1. I recommend you avoid this, as removing the SD Card Slot will likely require a hot air station. To avoid this problem altogether, make sure you remove all the old solder from the Wii U console before trying to solder the NAND-AID to the ground pad. The point of failure is the ground pad on the Wii U where the old solder would remain, it will fail there. Additionally make sure you have soldered all data points on the NAND-AID to their respective points on the Wii U board. If you have missed any of these the SD Card will not Erase properly inside minute and you will get this error. These are the most likely reasons for the error. As a last resort try another SD Card. I have had out of 45 consoles 3 SD Cards that just refused to work, they were Samsung/Sandisk cards that worked fine in a PC and even doing a test for read/write on them came back with no issues, but for some reason the Wii U console refused to work with them. Based on my experience this is a rare situation, but its a simple one to test for by trying another SD Card.