For anyone in the same predicament, what I did was download the latest Priiloader, install its boot.dol file in Preloader, and launch it. That made the System Menu appear as if it was a new Wii. From then I just used the ModMii wizard for new Wiis. At one point I had to interrupt the main...
I just purchased a used Wii and when turning it on, I see preloader v0.28 and this error:
Error autobooting systemmenu!
Ticket not found!
If I go into Homebrew Channel, I get this:
Error autobooting HBC, maybe title not installed?
Following advice from another thread, I copied the boot.elf...