You should
You should had updated before... you had so much effort patching to access eshop in 5.5.1 unnecessarily and you only needed to 5.5.4 and simplify all the process.
if you are on 5.5.1 cbhc right now, you will have to reinstall it again after updating. this is also so simple. why stay on lower version?
you can't use the same HDD for WiiU and vWii. You need separate HDDs.
Just to update everyone, I have just uninstalled CBHC. Rebooted. Installed the latest firmware (Which took the most time of 5 minutes). Rebooted again. Launched Brain training > HBC. Installed CBHC again. Rebooted. All is working great on the latest 5.5.4 firmware. Was easy so no fear if anyone else is in a similar boat; just make sure you uninstall CBHC before the firmware update (even though on EUR consoles the system menu xml is updated it should boot the stock menu, but better be safe than sorry).
I'm currently doing a NAND backup on 5.5.4. - Then after I will actually install some good stuff!
What cases do people recommend in 2019 to protect the gamepad? UK based please or something from china / aliexpress etc is fine.