Priiloader (based on the app Preloader) is an app that replaces the first part of the system menu that gets booted. Like this it is able to load before the actual Wii menu appears on the screen.
This gives it several advantages:
WARNING! Do not install Priiloader on the Wii U! This will instantly brick the virtual Wii mode!
1. Download the Priiloader pack and extract the apps folder to the root of your SD card. Don't change the folder structure! Let it overwrite/merge existing stuff if needed.
2. Download the hacks for priiloader and put the hacks_hash.ini file at the root of the SD card.
3. Run the priiloader installer with the HBC.
On the new screen press +. This will install Priiloader on your system.
If you get any errors about loader.ini or password.txt, ignore those.
It should now reboot in the Priiloader menu. If it doesn't, power off the wii, then power it back on and hold reset while it's booting until you see it.
4. The priiloader menu is white by default, you can change it to black in the settings if you prefer. If you want, you can install some system menu hacks now (by going to System Menu hacks).
Installing a file
One of the special functions of Priiloader is that it can autoboot any file instead of the system menu. Some apps (like crazyIntro) can't be used without it.
So here's how to do it:
1. The first thing to do is to put the dol you want to boot on the SD card. You have to place this dol at the root of the SD card (not in a folder). It is not needed to rename the file to boot.dol
2. Run priiloader (by holding the RESET button while the Wii boots.)
3. Now go to Install File. On the new screen, go to your dol and press A to install it. Wait for it to install and return to the main menu.
4. Now go to Settings. We need to change 2 things here:
Save the settings and restart the Wii to see the result.
Note that you can only access the system menu trough priiloader (or crazyIntro)!