You won't be able to use the homebrew loader anymore.What do you mean close the back door?
What do I delete and what do I install?If you reinstall the system menu, the Tiramisu coldboot get's removed. So if the menu doesn't work then, then we won't have access to tiramisu anymore
You should delete these two files which are bricked already, not the whole menu... Then after that reinstall the menu.Also won't it brick my wii u if I delete Wii U Menu