an Update...
Nothing I tried in the auto install part of the document worked. even tho I could see the DFU device appear using the mks5lboot utility, the setup still fails with the same as the image I attached.
So I tried the manual installation, this is in linux mint 20.3
I followed the manual instructions of my specific device pdf file very closely and I was able to get the firmware on the ipod, but the rockboxutility still failed to transfer the rockbox software.
I rebooted a few times and still it would sit at the attached screen shot. I felt stuck, I tried to remove the new fw using whatever method I could find and could not!
the problem now is the ipod was in read only mode so I couldn't transfer the zip file
I booted into my windows box and tried that manual setup, and it still failed in the same was as the images show.
At some point while rebooting and reconnecting, I was able to write to it in windows so I transferred the .rockbox over to the ipod.
I didn't write down what I was doing at this point as I had pretty much given up.
At some point I rebooted and voila, rockbox booted up and I could see the interface.
Needless to say I am a happy camper. But I am a little sadistic in that I want to repeat this whole process so I can understand what worked and what didn't work. I know it's crazy.
What steps do I need to do to restore the ipod to be an apple device? so I can repeat this whole thing?
Many Thanks