Right now, I was having some issues to play Zelda as well, after last Game updates from the last days or hours. However, I did something to get it working. This might work with you as well depending on your setup: what firmware version, signature patch method and blocking updates methods you're using.
Background: My setup is CBHC on 5.5.1 and when trying to launch Zelda, it was asking for a system update. The option I have for blocking future updates is deleting the 'update' folder as described here
https://gbatemp.net/threads/block-wii-u-system-updates-without-dns-blocking.477944/ (I don't use any DNS blocking)
Whit this blocking-updates method, I would have access to netfilx, youtube and internet browser without issues while preventing my system to update to 5.5.2 or newer. I stepped away from TubeHax method (set specific DNS) because I found it unreliable from time to time and couldn't access all those services/applications (netflix, youtube, internet browser) from my Wii U.
What I did today was to install latest Zelda BOTW update downloaded from wii u usb helper. Right now 12/16 11:44 PM Central US time the latest Zelda BOTW update version available on Wii U USB helper is v176 (1.4.0) as you can see below. I understand this update v176 was released on 12/7 by Nintendo:
However Nintendo released v192 (1.4.1) a couple of days ago but for some reason is not showing on Wii U Usb helper yet. I heard Nintendo released it but they pulled back from their servers next day for some reason. Anyway, let's hope it's just matter of time until it's available again on Wii U Usb helper to download as normal.
I also downloaded and installed latest DLC from Wii U USB Helper. Then when trying to run Zelda, it will say something like "your system requires an update" giving you two options: Yes or No. If you choose No, it will cancel leaving you on the Wii u menu (it won't launch the game). If you choose yes, you are taken to the system config->Update screen. Since I'm using the method which erased the 'update' folder, the system update attempt will fail leaving you in that system config->Update screen.
Then in order to have the game launched at this point is to make the system 'fail' to do the initial version check/update when trying to launch the game. This is: setting some dummy DNS like primary 1.1.1.1 secondary 0.0.0.0, or turn off your wifi, or block somehow your wii u ability to connect to internet, more specifically, to communicate with Nintendo update servers. What I used was to set up a dummy DNS and then launch the game, in this case, it will say something like "there's a problem trying to update, do you want to launch anyway?" giving you to options: Yes or No, you know what to choose here. Then I could launch Zelda BOTW updated to 1.4.0 and latest DLC installed (the champion's balad)
