I have a eu Wii U on 5.5.5 and i wanted to hack it with haxchi, and I remembered that I've gotten kawashima brain age for free at the time, but when
I'm getting this error when i'm trying to update the console to the latest firmware 5.5.6U, i already uninstalled Coldboot Haxchi, unplugged my external HDD and restarted the console, still nothing. :
Wii U Architecture | A Practical Analysis
Wii-U-Update 5.5.2/5.5.3/5.5.4/5.5.5 – und nun? – WiiDatabase
How to Make Your Wii U Useful Again With Homebrew | Wii u, Home brewing, Technology diy
Wii U Hacks Guide - Install Haxchi CFW (eShop DS Game Required) - CFWaifu
HOW TO INSTALL HAXCHI+HOMEBREW ON WIIU SUPER EASY! - YouTube
Using Haxchi to Load Sm4sh Mods (5.5.2 & 5.5.1) [Super Smash Bros. (Wii U)] [Tutorials]
How to Soft-Mod WiiU - Pt 1 - Install: Haxchi on WiiU Firmware 5.5.2/5.5.3 - Get Permanent Hb & CFW - YouTube
How to Hack Wii U Homebrew & Play Games on Wii U [Full Guide] - MiniTool Partition Wizard
Help with Haxchi after update?? (see comments for description) : r/WiiUHacks