Just stopping buy to say the same thing happened to me. Everything went well then on that last step, black screen. and yes Cakes was acting like a ass not wanting to boot sometimes.
although i ended up accidentally changing my nand with no way of going back bc i didn't know you needed a gamecube controller to restore it (i have a wii minus/1.1, which doesn't have gamecube controller support)
and if i find the sd card i have my NAND backed up on, i can not only restore the NAND if i solder the right part in, but i can also put my NAND on dolphin, then i can play dolphin online, like PMEX Remix or MKWii Riibalanced