Trying to recover 67's prerecorded magnetic cards

[aurelio]

Hi all, back again on this kind of issue.
I'm trying to rewrite the original card from a pack . I get "error" with different reader, different machines.
I used another identical prerecorded 100% working card and the "Write-Protect Defeat Card".
unsuccesful after several attempts, I mean that after a reading from the "good" card (program loaded on the 67 or 97, not manually loaded) I rewrote (I guess) the "damaged card", first side >>>>the other side>>>>0.00.
Then I reset the calculator trying to read the "newly written" card....no way>>>Error
I play the game smoothly with a fresh card, but not with the original ones...

I'm not sure if I'm doing well: the Crd and the 0.00 display after two passages sounds good, but the result is bad, does it means that the card is not rewritable at all, a defective media?