Yep been there.
You need to remove the boot.dol file currently in the root of your sd card - from when you installed HBC. Put a copy of whatever boot.dol loader you are going to try into the root of your sd card. Run preloader and choose install file. It will find your boot.dol file and list it. Select it and install.Then still in preloader go to the hacks and change the first option to boot into FILE. This will then run whatever boot.dol you have just installed when your wii is turned on.
To revert back just change the hack option back to SYSTEM or HBC.
You need to remove the boot.dol file currently in the root of your sd card - from when you installed HBC. Put a copy of whatever boot.dol loader you are going to try into the root of your sd card. Run preloader and choose install file. It will find your boot.dol file and list it. Select it and install.Then still in preloader go to the hacks and change the first option to boot into FILE. This will then run whatever boot.dol you have just installed when your wii is turned on.
To revert back just change the hack option back to SYSTEM or HBC.