I had the same issue, either it would freeze and required a hard boot, black screen with some pixels, one time it had a race attack error.
I followed what some other's have explained and it worked very quickly and works almost everytime after.
First time ever? I did this first.
Delete all browser data/cookies/cache, uncheck remember username/password.
have your local http up and hosting payload532.html, browse to that website and save as favourites.
Exit Internet Browser
Turn off wiiu
power it back on and go to internet browser.
it should have saved your webhost as a favourite pointing to your local computer with the html source on the first tab.
Run AIO kernel.
It looks like the HTML code is an array buffer overflow attack. I seems it needs to be in a particular memory space for it to work successfully. If you have a Browser Cache of a session and it continually freezees and it just doesnt work in after a few tries, clear the browser cache and start over. I believe this allows the code to run in a new space where it might be successful. The reason why I believe this is because once you run the AIO Kernel successfully, as long as you don't clear the browser cache it seems to run everytime afterwards (regardless of how many times you power off and on your console) successfully within 1-3 tries (as if the browser cache is now in the right memory space to be exploited). It's a breeze after the first time.
You know you're in the right "place" when it work quickly and gives you actual information rather then just freezing forever or black screen.
Once it's all setup and you have the AIO Kernel working, never touch the broswer cache and it should run the exploit almost flawlessly afterwards.
Maybe someone else can confirm my suspicions.
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