Hey, I have a theory why original DL/DVD9 doesn't work on Wiikey. First take a look at my post
here. In summary I wanted to use v1.9b so the DVD drive can read my backups at 6x instead of 3x on 1.9g. SL disc reads at 6x while surprising DL disc still reads at 3x. Now if I remember didn't Wiikey team release 1.9b to support DL disc? If so, I would assume the DL support was for GCN games (using GCOS) because GCN games are read at 3x! My theory here is that the reason why it couldn't read the original DL disc because Wiikey assume it's a GCN disc and couldn't read the GCN "header/TOC (or whatever's called)" on the Wii DL disc thus failed/give the disc read error.