... the floppy cable within the drive cage itself ...
It's been so long since I've seen a 2/10 in it's original state I'd forgotten all about this (and a whole lot of other things as you've all prolly noticed from my posts -- apologies for the errors).
On the 2/10, the rear of the floppy drive is difficult to access in the drive cage as there isn't much space below the Widget, and the cooling fan is partially obstructing it.
So to make it easier to disconnect/remove the drive cage, there is a short 20 pin ribbon cable extension (about 6" / 15cm long) with a flanged male connector mounted to the rear of the drive cage beside the fan, and a female connector that plugs into the drive. When you remove the drive cage, this short cable goes with it. The cable in the chassis plugs into this extension rather than the drive itself.
On my 2/10, this short extension is indeed a rainbow ribbon cable, whereas the chassis mounted ribbon cables are all grey.
edit: since this is a straight through extension, OP could eliminate this as a potential source of problems by connecting the FEMU directly to the grey chassis cable.
