Holy thread bump.
@Shaneee @Edhawk
So I've just wasted an hour messing about again with this...
I created a fresh USBMap.kext, using the tool, updated all my kexts/OC, made the USB, set my config.plist to be an iMac20,2 like Ed said, made sure it was all in the config.plist.
Tested all of...