Wii black screen -- help

Hi All,

I installed a few games as wads via wad manager (so they show up on menu as wiiware),
and it worked perfect, game icons shown on wii menu, loaded via usb drive.
I then added 2 more games via the wad manager-
and when I returned to the wii menu it gone black, and stuck.

now, when I start the wii, I get the warning screen, I hit the A button, then it plays 2 seconds of the wii menu music (screen black) and it gets stuck in silent black screen.
No Priiloader installed. I do have an old BootMii backup, but since BootMii was installed as ISO (and not on boot2) I can't get to load BootMii :(

It's a PAL, 4.1E system, with WiiKey1.
Does anyone have any idea how to get around this? Or maybe to get the BootMii backup back?

Many thanks!