In general, i don't recommend updating... We don't know if Big N will patches one day Haxchi...
You could have used NNU-Patcher (From the Homebrew Launcher [Download it via HBAppStore if not present]) & after that launched the eShop in 5.5.1...
(Don't worry if you did but, in the future don't do updates anymore....)
As of now, its perfectly safe to be on the latest Wii U firmware (5.5.2) regardless if you've already hacked or if you still intend to hack (though hacking on 5.5.2 isn't quite as easy since you have to use sleepyhax which isn't the most reliable method, but it does work). Have CHBC on 5.5.2 and it works like a charm.