OK, I got it! For some reason I had overlooked the mfu ‘restore’ command as it is described as ‘Restore a dump onto a MFU MAGIC tag’ and I was not using a magic tag… I tried it and it worked on a non magic tag! I had to manually write 3 protected blocks (41,42 and 43) to change the password from default FFFFFFFF to the one I needed based on the new UID of the blank tag and to match exactly the original (except for the UID as my tags do not allow writing blocks 00 and 01).Now the copy works perfectly well.
Thanks to Equipter for clarifying the file access which allowed me to analyze and edit the dump before writing it.